feat(crm): Phase 2.1 Custom Fields — backend + frontend integration

Backend (CRM expert): Custom field definitions CRUD, bulk value upsert, 7 endpoints, Prisma schema with CustomFieldDef + CustomFieldValue tables. Frontend: Types, API, hooks, admin settings page with field management, CustomFieldsDisplay for detail pages, CustomFieldsForm for edit modals. Also fix Vite allowedHosts for insight.xinion.lan. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-06-24 23:56:40 +02:00 · 2026-03-12 18:22:57 +01:00 · 2026-03-12 18:22:57 +01:00 · aaedf68085
commit aaedf68085
parent 405ab5f038
30 changed files with 2645 additions and 34 deletions
--- a/docs/INSIGHT-CRM.md
+++ b/docs/INSIGHT-CRM.md
@ -2193,3 +2193,101 @@ Bitte fuer jedes abgeschlossene Feature einen Eintrag in diese Datei schreiben:
 ---

 *Bitte neue Eintraege unten anfuegen. Format: `## YYYY-MM-DD | Absender: Betreff`*
+
+---
+
+## 2026-03-12 | CRM-Backend: Phase 2.1 — Custom Fields System
+
+### Neue Endpoints
+
+| Methode | Pfad | Beschreibung |
+|---------|------|-------------|
+| `POST` | `/api/v1/crm/custom-fields` | Feld-Definition erstellen |
+| `GET` | `/api/v1/crm/custom-fields?entityType=PERSON` | Alle Feld-Definitionen auflisten (optional nach Entity-Typ gefiltert) |
+| `GET` | `/api/v1/crm/custom-fields/:id` | Einzelne Feld-Definition abrufen |
+| `PATCH` | `/api/v1/crm/custom-fields/:id` | Definition aktualisieren (Label, Options, Position, Required) |
+| `DELETE` | `/api/v1/crm/custom-fields/:id` | Definition loeschen (CASCADE auf alle gespeicherten Werte!) |
+| `PUT` | `/api/v1/crm/custom-fields/:entityId/values` | Custom-Field-Werte fuer eine Entity setzen (Bulk-Upsert) |
+| `GET` | `/api/v1/crm/custom-fields/:entityId/values` | Custom-Field-Werte fuer eine Entity lesen |
+
+### Schema-Aenderungen
+
+**Neue Enums:**
+- `CustomFieldEntityType`: PERSON, COMPANY, DEAL
+- `CustomFieldType`: TEXT, TEXTAREA, NUMBER, DATE, DROPDOWN, MULTI_SELECT, CHECKBOX, URL
+
+**Neue Tabellen:**
+
+| Tabelle | Beschreibung |
+|---------|-------------|
+| `crm_custom_field_defs` | Feld-Definitionen pro Tenant + Entity-Typ. Unique: `[tenant_id, entity_type, name]`. Felder: entityType, name (Auto-Slug), label, fieldType (immutable), options (JSONB fuer DROPDOWN/MULTI_SELECT), isRequired, position |
+| `crm_custom_field_values` | Gespeicherte Werte. Unique: `[field_def_id, entity_id]`. Spalten pro Typ: valueText, valueNumber, valueDate, valueBoolean, valueJson. FK auf Definitionen mit CASCADE Delete |
+
+**SQL Migration:** `prisma/migrations/20260312_phase2_custom_fields/migration.sql`
+
+### Response-Aenderungen
+
+**Contact-Detail, Company-Detail, Deal-Detail** enthalten jetzt ein neues Feld `customFields`:
+
+```json
+{
+  "id": "...",
+  "firstName": "Max",
+  "customFields": [
+    {
+      "fieldDefId": "uuid",
+      "name": "kundennummer",
+      "label": "Kundennummer",
+      "fieldType": "TEXT",
+      "value": "KD-12345"
+    },
+    {
+      "fieldDefId": "uuid",
+      "name": "segment",
+      "label": "Segment",
+      "fieldType": "DROPDOWN",
+      "value": "A"
+    },
+    {
+      "fieldDefId": "uuid",
+      "name": "newsletter",
+      "label": "Newsletter",
+      "fieldType": "CHECKBOX",
+      "value": null
+    }
+  ]
+}
+```
+
+Das Array enthaelt ALLE definierten Custom Fields fuer den jeweiligen Entity-Typ (auch ohne Wert = `value: null`), sortiert nach `position`. Das Frontend bekommt so immer die vollstaendige Feldliste fuer Formular-Rendering.
+
+### Value-Mapping nach Feldtyp
+
+| FieldType | JS-Typ | Beispiel |
+|-----------|--------|---------|
+| TEXT, TEXTAREA, URL | string | `"KD-12345"` |
+| NUMBER | number | `42.5` |
+| DATE | string (ISO) | `"2026-01-15T00:00:00.000Z"` |
+| CHECKBOX | boolean | `true` |
+| DROPDOWN | string (single select) | `"premium"` |
+| MULTI_SELECT | string[] | `["tag-a", "tag-b"]` |
+
+### Wichtige Regeln
+
+- **name** (interner Slug) wird automatisch aus dem Label generiert (Umlaute: ae/oe/ue/ss). Unique pro Tenant + Entity-Typ.
+- **entityType** und **fieldType** sind nach Erstellung **nicht mehr aenderbar** (wuerde bestehende Werte invalidieren).
+- **DROPDOWN/MULTI_SELECT** erfordern `options`: `[{value: "a", label: "Segment A"}, ...]`. Bei Wert-Speicherung wird gegen die Options validiert.
+- **DELETE** einer Definition loescht automatisch alle gespeicherten Werte (CASCADE).
+- **Orphan-Cleanup**: Beim Loeschen eines Contacts/Company/Deal werden zugehoerige Custom-Field-Werte automatisch entfernt.
+- **isRequired** wird aktuell nur client-seitig ausgewertet (das Flag wird mitgeliefert). Server-seitige Pflichtfeld-Pruefung kann spaeter ergaenzt werden.
+
+### TODO fuer Frontend
+
+1. **Admin-Bereich:** CRUD-UI fuer Custom Field Definitionen (pro Entity-Typ: PERSON, COMPANY, DEAL)
+   - Felder: Label (→ Slug auto), Feldtyp (immutable nach Erstellung), Options-Editor fuer DROPDOWN/MULTI_SELECT, Pflichtfeld-Toggle, Drag&Drop fuer Position
+2. **Entity-Detail-Pages:** `customFields`-Array aus Response auslesen und dynamisch rendern
+   - Pro Feldtyp: Text-Input, Textarea, Number-Input, Date-Picker, Select, Multi-Select, Checkbox, URL-Input
+3. **Entity-Formulare:** Custom Fields im Erstellen/Bearbeiten-Formular einbinden
+   - `PUT /custom-fields/:entityId/values` nach Entity-Speichern aufrufen
+   - `isRequired` client-seitig validieren
+4. **API-Aufrufe:** `GET /custom-fields?entityType=PERSON` fuer Feld-Definitionen, `PUT/GET /custom-fields/:entityId/values` fuer Werte
--- a/packages/crm-service/Summarize.md
+++ b/packages/crm-service/Summarize.md
@ -26,11 +26,12 @@ packages/crm-service/
    redis/              — RedisService (Token-Blocklist, Cache, Distributed Locks)
    auth/               — JWT Strategy (RS256), JwtAuthGuard, RolesGuard, TenantGuard
    common/             — Decorators (@Public, @Roles, @CurrentUser), Pagination, ExceptionFilter, Shared DTOs (contact-info, owner)
-    companies/          — CRUD: Unternehmen (Multi-Value emails/phones, Owner m:n, Status, Lexware ERP-Push)
-    contacts/           — CRUD: Kontakte (Multi-Value emails/phones, Owner m:n, Status, Events)
+    custom-fields/      — Custom Fields System (Phase 2.1): Definitionen + Werte CRUD, Entity-Integration
+    companies/          — CRUD: Unternehmen (Multi-Value emails/phones, Owner m:n, Status, Lexware ERP-Push, Custom Fields)
+    contacts/           — CRUD: Kontakte (Multi-Value emails/phones, Owner m:n, Status, Events, Custom Fields)
    activities/         — CRUD: Aktivitaeten (NOTE, CALL, EMAIL, MEETING, TASK, FOLLOWUP; contactId+companyId optional)
    pipelines/          — CRUD: Sales-Pipelines mit Stages (inkl. Stage-Update)
-    deals/              — CRUD: Vorgaenge mit Pipeline/Stage/Contact/Company + DealVouchers + LostReason + Owner m:n + Events
+    deals/              — CRUD: Vorgaenge mit Pipeline/Stage/Contact/Company + DealVouchers + LostReason + Owner m:n + Events + Custom Fields
    owners/             — Shared Owner-Service (Contact/Company/Deal Owners, Upsert, Rollen)
    events/             — CRM Event Publisher (Redis Pub/Sub) + Activity Due-Soon Scheduler
    industries/         — CRUD: Branchen (admin-konfigurierbar, mit Farbe)
@ -73,6 +74,8 @@ packages/crm-service/
 - **Contract** — Vertraege (DB-Modell vorhanden, UI-Platzhalter)
 - **LexwareVoucher** — Gecachte Belege aus Lexware Office
 - **DealVoucher** — Join-Table Deal <-> Beleg (m:n mit Audit-Trail)
+- **CustomFieldDef** — Benutzerdefinierte Feld-Definitionen (Phase 2.1): entityType, name (Slug), label, fieldType, options (JSONB), isRequired, position. Unique: [tenantId, entityType, name]
+- **CustomFieldValue** — Gespeicherte Werte (Phase 2.1): fieldDefId, entityId (generisch), valueText/valueNumber/valueDate/valueBoolean/valueJson. Unique: [fieldDefId, entityId]. CASCADE Delete bei Definition-Loeschung

 ### Entity-Beziehungen

@ -94,6 +97,7 @@ PipelineStage (1) --< (n) Deal           — stageId
 Deal (1) --< (n) DealVoucher             — dealId (Cascade)
 LexwareVoucher (1) --< (n) DealVoucher   — voucherId (Cascade)
 RelationshipType (1) --< (n) CompanyRelationship — relationshipTypeId
+CustomFieldDef (1) --< (n) CustomFieldValue     — fieldDefId (Cascade)
 ```

 ### API-Endpunkte
@ -128,6 +132,14 @@ RelationshipType (1) --< (n) CompanyRelationship — relationshipTypeId
 | GET/POST | /api/v1/crm/deals | Liste / Erstellen |
 | GET/PATCH/DELETE | /api/v1/crm/deals/:id | Detail / Update / Delete |
 | GET | /health | Health-Check (DB, Redis, Lexware) |
+| **Custom Fields** | | |
+| POST | /api/v1/crm/custom-fields | Feld-Definition erstellen |
+| GET | /api/v1/crm/custom-fields?entityType=PERSON | Definitionen auflisten (nach Entity-Typ) |
+| GET | /api/v1/crm/custom-fields/:id | Definition abrufen |
+| PATCH | /api/v1/crm/custom-fields/:id | Definition aktualisieren |
+| DELETE | /api/v1/crm/custom-fields/:id | Definition loeschen (CASCADE) |
+| PUT | /api/v1/crm/custom-fields/:entityId/values | Werte setzen (Bulk-Upsert) |
+| GET | /api/v1/crm/custom-fields/:entityId/values | Werte lesen |
 | **Lexware Kontakte** | | |
 | GET | /api/v1/crm/lexware/contacts/search | Lexware-Kontakte suchen |
 | POST | /api/v1/crm/lexware/contacts/link-company | Company verknuepfen |
@ -184,15 +196,14 @@ RelationshipType (1) --< (n) CompanyRelationship — relationshipTypeId
 - `20260310_add_lexware_integration` — Lexware Office Integration
 - `20260311_add_company_detail_overhaul` — Company Detail Overhaul
 - `20260312_phase1_schema_expansion` — Phase 1: Enums, Multi-Value, Owner, LostReason
+- `20260312_phase2_custom_fields` — Phase 2.1: Custom Fields (Definitionen + Werte)

 ### Naechste Schritte

-1. Migration `20260312_phase1_schema_expansion` auf Server anwenden
+1. Migration `20260312_phase2_custom_fields` auf Server anwenden
 2. Container neu bauen und deployen
-3. Frontend: Multi-Value Email/Phone UI implementieren
-4. Frontend: Owner-Management UI
-5. Frontend: EntityStatus statt isActive verwenden
-6. Frontend: LostReason bei Deal-Verlust einblenden
-7. Phase 2: Office 365 E-Mail Integration (Planer-Briefing vorhanden)
-8. Phase 3: Kontakt-Zusammenfuehrung (Merge)
-9. Phase 4: Aktivitaets-Erweiterung + Dashboard Widgets
+3. Frontend: Custom Fields Admin-UI + Entity-Integration
+4. Phase 2.2: Kontakt-Import (CSV, Excel, vCard)
+5. Phase 2.3: Forecast-Endpoint (Probability-Feld auf PipelineStage)
+6. Phase 2.4: Firmendaten-Anreicherung (Data Enrichment)
+7. Phase 2.5: Berechtigungsmodell (Sichtbarkeitsfilter)
--- a/packages/crm-service/prisma/crm.schema.prisma
+++ b/packages/crm-service/prisma/crm.schema.prisma
@ -717,6 +717,81 @@ model DealOwner {
  @@schema("app_crm")
 }

+// --------------------------------------------------------
+// Phase 2.1 Enums — Custom Fields
+// --------------------------------------------------------
+enum CustomFieldEntityType {
+  PERSON
+  COMPANY
+  DEAL
+
+  @@schema("app_crm")
+}
+
+enum CustomFieldType {
+  TEXT
+  TEXTAREA
+  NUMBER
+  DATE
+  DROPDOWN
+  MULTI_SELECT
+  CHECKBOX
+  URL
+
+  @@schema("app_crm")
+}
+
+// --------------------------------------------------------
+// CustomFieldDef - Benutzerdefinierte Feld-Definitionen (Phase 2.1)
+// --------------------------------------------------------
+model CustomFieldDef {
+  id         String                @id @default(uuid()) @db.Uuid
+  tenantId   String                @map("tenant_id") @db.Uuid
+  entityType CustomFieldEntityType @map("entity_type")
+  name       String                @db.VarChar(200)
+  label      String                @db.VarChar(200)
+  fieldType  CustomFieldType       @map("field_type")
+  options    Json?                 @db.JsonB
+  isRequired Boolean               @default(false) @map("is_required")
+  position   Int                   @default(0)
+  createdAt  DateTime              @default(now()) @map("created_at")
+  updatedAt  DateTime              @updatedAt @map("updated_at")
+
+  values CustomFieldValue[]
+
+  @@unique([tenantId, entityType, name])
+  @@index([tenantId])
+  @@index([tenantId, entityType])
+  @@map("crm_custom_field_defs")
+  @@schema("app_crm")
+}
+
+// --------------------------------------------------------
+// CustomFieldValue - Benutzerdefinierte Feld-Werte (Phase 2.1)
+// --------------------------------------------------------
+model CustomFieldValue {
+  id           String    @id @default(uuid()) @db.Uuid
+  tenantId     String    @map("tenant_id") @db.Uuid
+  fieldDefId   String    @map("field_def_id") @db.Uuid
+  entityId     String    @map("entity_id") @db.Uuid
+  valueText    String?   @map("value_text") @db.Text
+  valueNumber  Decimal?  @map("value_number") @db.Decimal(15, 4)
+  valueDate    DateTime? @map("value_date")
+  valueBoolean Boolean?  @map("value_boolean")
+  valueJson    Json?     @map("value_json") @db.JsonB
+  createdAt    DateTime  @default(now()) @map("created_at")
+  updatedAt    DateTime  @updatedAt @map("updated_at")
+
+  fieldDef CustomFieldDef @relation(fields: [fieldDefId], references: [id], onDelete: Cascade)
+
+  @@unique([fieldDefId, entityId])
+  @@index([tenantId])
+  @@index([tenantId, entityId])
+  @@index([fieldDefId])
+  @@map("crm_custom_field_values")
+  @@schema("app_crm")
+}
+
 // --------------------------------------------------------
 // TradeEvent - Messe-/Event-Timer (admin-konfigurierbar)
 // --------------------------------------------------------
--- a/packages/crm-service/prisma/migrations/20260312_phase2_custom_fields/migration.sql
+++ b/packages/crm-service/prisma/migrations/20260312_phase2_custom_fields/migration.sql
@ -0,0 +1,86 @@
+-- ============================================================
+-- Phase 2.1: Custom Fields System
+-- Benutzerdefinierte Felder fuer PERSON, COMPANY, DEAL
+-- ============================================================
+
+-- --------------------------------------------------------
+-- 1. Neue Enums
+-- --------------------------------------------------------
+
+CREATE TYPE "app_crm"."CustomFieldEntityType" AS ENUM (
+  'PERSON', 'COMPANY', 'DEAL'
+);
+
+CREATE TYPE "app_crm"."CustomFieldType" AS ENUM (
+  'TEXT', 'TEXTAREA', 'NUMBER', 'DATE',
+  'DROPDOWN', 'MULTI_SELECT', 'CHECKBOX', 'URL'
+);
+
+-- --------------------------------------------------------
+-- 2. crm_custom_field_defs — Feld-Definitionen
+-- --------------------------------------------------------
+
+CREATE TABLE "app_crm"."crm_custom_field_defs" (
+  "id"          UUID NOT NULL DEFAULT gen_random_uuid(),
+  "tenant_id"   UUID NOT NULL,
+  "entity_type" "app_crm"."CustomFieldEntityType" NOT NULL,
+  "name"        VARCHAR(200) NOT NULL,
+  "label"       VARCHAR(200) NOT NULL,
+  "field_type"  "app_crm"."CustomFieldType" NOT NULL,
+  "options"     JSONB,
+  "is_required" BOOLEAN NOT NULL DEFAULT false,
+  "position"    INTEGER NOT NULL DEFAULT 0,
+  "created_at"  TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  "updated_at"  TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  CONSTRAINT "crm_custom_field_defs_pkey" PRIMARY KEY ("id")
+);
+
+CREATE UNIQUE INDEX "crm_custom_field_defs_tenant_entity_name_key"
+  ON "app_crm"."crm_custom_field_defs"("tenant_id", "entity_type", "name");
+
+CREATE INDEX "crm_custom_field_defs_tenant_id_idx"
+  ON "app_crm"."crm_custom_field_defs"("tenant_id");
+
+CREATE INDEX "crm_custom_field_defs_tenant_entity_idx"
+  ON "app_crm"."crm_custom_field_defs"("tenant_id", "entity_type");
+
+-- --------------------------------------------------------
+-- 3. crm_custom_field_values — Feld-Werte
+-- --------------------------------------------------------
+
+CREATE TABLE "app_crm"."crm_custom_field_values" (
+  "id"            UUID NOT NULL DEFAULT gen_random_uuid(),
+  "tenant_id"     UUID NOT NULL,
+  "field_def_id"  UUID NOT NULL,
+  "entity_id"     UUID NOT NULL,
+  "value_text"    TEXT,
+  "value_number"  DECIMAL(15, 4),
+  "value_date"    TIMESTAMP(3),
+  "value_boolean" BOOLEAN,
+  "value_json"    JSONB,
+  "created_at"    TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  "updated_at"    TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  CONSTRAINT "crm_custom_field_values_pkey" PRIMARY KEY ("id")
+);
+
+CREATE UNIQUE INDEX "crm_custom_field_values_field_entity_key"
+  ON "app_crm"."crm_custom_field_values"("field_def_id", "entity_id");
+
+CREATE INDEX "crm_custom_field_values_tenant_id_idx"
+  ON "app_crm"."crm_custom_field_values"("tenant_id");
+
+CREATE INDEX "crm_custom_field_values_tenant_entity_idx"
+  ON "app_crm"."crm_custom_field_values"("tenant_id", "entity_id");
+
+CREATE INDEX "crm_custom_field_values_field_def_id_idx"
+  ON "app_crm"."crm_custom_field_values"("field_def_id");
+
+-- --------------------------------------------------------
+-- 4. Foreign Key: Values -> Definitions (CASCADE)
+-- --------------------------------------------------------
+
+ALTER TABLE "app_crm"."crm_custom_field_values"
+  ADD CONSTRAINT "crm_custom_field_values_field_def_fkey"
+    FOREIGN KEY ("field_def_id")
+    REFERENCES "app_crm"."crm_custom_field_defs"("id")
+    ON DELETE CASCADE ON UPDATE CASCADE;
--- a/packages/crm-service/src/app.module.ts
+++ b/packages/crm-service/src/app.module.ts
@ -21,6 +21,7 @@ import { RelationshipTypesModule } from './relationship-types/relationship-types
 import { CompanyRelationshipsModule } from './company-relationships/company-relationships.module';
 import { TradeEventsModule } from './trade-events/trade-events.module';
 import { CrmEventsModule } from './events/crm-events.module';
+import { CustomFieldsModule } from './custom-fields/custom-fields.module';

@Module({
  imports: [
@ -45,6 +46,7 @@ import { CrmEventsModule } from './events/crm-events.module';
    CompanyRelationshipsModule,
    TradeEventsModule,
    CrmEventsModule,
+    CustomFieldsModule,
  ],
  providers: [
    {
--- a/packages/crm-service/src/companies/companies.module.ts
+++ b/packages/crm-service/src/companies/companies.module.ts
@ -4,9 +4,10 @@ import { CompaniesService } from './companies.service';
 import { CrmPrismaModule } from '../prisma/crm-prisma.module';
 import { LexwareModule } from '../lexware/lexware.module';
 import { OwnersModule } from '../owners/owners.module';
+import { CustomFieldsModule } from '../custom-fields/custom-fields.module';

@Module({
-  imports: [CrmPrismaModule, LexwareModule, OwnersModule],
+  imports: [CrmPrismaModule, LexwareModule, OwnersModule, CustomFieldsModule],
  controllers: [CompaniesController],
  providers: [CompaniesService],
  exports: [CompaniesService],
--- a/packages/crm-service/src/companies/companies.service.ts
+++ b/packages/crm-service/src/companies/companies.service.ts
@ -4,6 +4,8 @@ import { CreateCompanyDto } from './dto/create-company.dto';
 import { UpdateCompanyDto } from './dto/update-company.dto';
 import { QueryCompaniesDto } from './dto/query-companies.dto';
 import { LexwareContactsService } from '../lexware/lexware-contacts.service';
+import { CustomFieldsService } from '../custom-fields/custom-fields.service';
+import { CustomFieldEntityType } from '../custom-fields/dto/create-custom-field.dto';
 import { Prisma } from '.prisma/crm-client';
 import { EntityStatus } from '../common/dto/contact-info.dto';

@ -14,6 +16,7 @@ export class CompaniesService {
  constructor(
    private readonly prisma: CrmPrismaService,
    private readonly lexwareContacts: LexwareContactsService,
+    private readonly customFieldsService: CustomFieldsService,
  ) {}

  async create(tenantId: string, userId: string, dto: CreateCompanyDto) {
@ -227,7 +230,14 @@ export class CompaniesService {
      throw new NotFoundException('Unternehmen nicht gefunden');
    }

-    return company;
+    // Custom Fields anhaengen
+    const customFields = await this.customFieldsService.getCustomFieldsForEntity(
+      tenantId,
+      CustomFieldEntityType.COMPANY,
+      id,
+    );
+
+    return { ...company, customFields };
  }

  async update(
@ -339,6 +349,11 @@ export class CompaniesService {
  async remove(tenantId: string, id: string) {
    await this.findOne(tenantId, id);

+    // Custom Field Values entfernen (entityId hat keinen FK, daher manuell)
+    await this.prisma.customFieldValue.deleteMany({
+      where: { tenantId, entityId: id },
+    });
+
    return this.prisma.company.delete({ where: { id } });
  }
 }
--- a/packages/crm-service/src/contacts/contacts.module.ts
+++ b/packages/crm-service/src/contacts/contacts.module.ts
@ -3,9 +3,10 @@ import { ContactsController } from './contacts.controller';
 import { ContactsService } from './contacts.service';
 import { LexwareModule } from '../lexware/lexware.module';
 import { OwnersModule } from '../owners/owners.module';
+import { CustomFieldsModule } from '../custom-fields/custom-fields.module';

@Module({
-  imports: [LexwareModule, OwnersModule],
+  imports: [LexwareModule, OwnersModule, CustomFieldsModule],
  controllers: [ContactsController],
  providers: [ContactsService],
  exports: [ContactsService],
--- a/packages/crm-service/src/contacts/contacts.service.ts
+++ b/packages/crm-service/src/contacts/contacts.service.ts
@ -5,6 +5,8 @@ import { UpdateContactDto } from './dto/update-contact.dto';
 import { QueryContactsDto } from './dto/query-contacts.dto';
 import { LexwareContactsService } from '../lexware/lexware-contacts.service';
 import { CrmEventPublisher } from '../events/crm-event-publisher.service';
+import { CustomFieldsService } from '../custom-fields/custom-fields.service';
+import { CustomFieldEntityType } from '../custom-fields/dto/create-custom-field.dto';
 import { Prisma } from '.prisma/crm-client';
 import { EntityStatus } from '../common/dto/contact-info.dto';

@ -16,6 +18,7 @@ export class ContactsService {
    private readonly prisma: CrmPrismaService,
    private readonly lexwareContacts: LexwareContactsService,
    private readonly eventPublisher: CrmEventPublisher,
+    private readonly customFieldsService: CustomFieldsService,
  ) {}

  async create(tenantId: string, userId: string, dto: CreateContactDto) {
@ -186,7 +189,14 @@ export class ContactsService {
      throw new NotFoundException('Kontakt nicht gefunden');
    }

-    return contact;
+    // Custom Fields anhaengen
+    const customFields = await this.customFieldsService.getCustomFieldsForEntity(
+      tenantId,
+      CustomFieldEntityType.PERSON,
+      id,
+    );
+
+    return { ...contact, customFields };
  }

  async update(
@ -305,6 +315,11 @@ export class ContactsService {
  async remove(tenantId: string, id: string) {
    await this.findOne(tenantId, id);

+    // Custom Field Values entfernen (entityId hat keinen FK, daher manuell)
+    await this.prisma.customFieldValue.deleteMany({
+      where: { tenantId, entityId: id },
+    });
+
    return this.prisma.contact.delete({ where: { id } });
  }
 }
--- a/packages/crm-service/src/custom-fields/custom-fields.controller.ts
+++ b/packages/crm-service/src/custom-fields/custom-fields.controller.ts
@ -0,0 +1,156 @@
+// ============================================================
+// CustomFieldsController — REST-Endpoints fuer Custom Fields
+// ============================================================
+
+import {
+  Controller,
+  Get,
+  Post,
+  Patch,
+  Put,
+  Delete,
+  Body,
+  Param,
+  Query,
+  ParseUUIDPipe,
+  HttpCode,
+  HttpStatus,
+  UseGuards,
+} from '@nestjs/common';
+import {
+  ApiTags,
+  ApiOperation,
+  ApiBearerAuth,
+  ApiParam,
+  ApiQuery,
+} from '@nestjs/swagger';
+import { CustomFieldsService } from './custom-fields.service';
+import { CreateCustomFieldDto, CustomFieldEntityType } from './dto/create-custom-field.dto';
+import { UpdateCustomFieldDto } from './dto/update-custom-field.dto';
+import { SetCustomFieldValuesDto } from './dto/set-custom-field-values.dto';
+import { CurrentUser, JwtPayload } from '../common/decorators';
+import { TenantGuard } from '../auth/guards/tenant.guard';
+import { singleResponse } from '../common/dto/pagination.dto';
+
+@ApiTags('Custom Fields')
+@ApiBearerAuth('access-token')
+@UseGuards(TenantGuard)
+@Controller('custom-fields')
+export class CustomFieldsController {
+  constructor(private readonly customFieldsService: CustomFieldsService) {}
+
+  // --------------------------------------------------------
+  // Definitionen
+  // --------------------------------------------------------
+
+  @Post()
+  @HttpCode(HttpStatus.CREATED)
+  @ApiOperation({ summary: 'Feld-Definition erstellen' })
+  async createDefinition(
+    @CurrentUser() user: JwtPayload,
+    @Body() dto: CreateCustomFieldDto,
+  ) {
+    const definition = await this.customFieldsService.createDefinition(
+      user.tenantId!,
+      dto,
+    );
+    return singleResponse(definition);
+  }
+
+  @Get()
+  @ApiOperation({ summary: 'Alle Feld-Definitionen auflisten' })
+  @ApiQuery({
+    name: 'entityType',
+    required: false,
+    enum: CustomFieldEntityType,
+    description: 'Filter nach Entity-Typ',
+  })
+  async findAllDefinitions(
+    @CurrentUser() user: JwtPayload,
+    @Query('entityType') entityType?: CustomFieldEntityType,
+  ) {
+    const definitions = await this.customFieldsService.findAllDefinitions(
+      user.tenantId!,
+      entityType,
+    );
+    return { data: definitions };
+  }
+
+  @Get(':id')
+  @ApiOperation({ summary: 'Feld-Definition abrufen' })
+  @ApiParam({ name: 'id', type: 'string', format: 'uuid' })
+  async findOneDefinition(
+    @CurrentUser() user: JwtPayload,
+    @Param('id', ParseUUIDPipe) id: string,
+  ) {
+    const definition = await this.customFieldsService.findOneDefinition(
+      user.tenantId!,
+      id,
+    );
+    return singleResponse(definition);
+  }
+
+  @Patch(':id')
+  @ApiOperation({ summary: 'Feld-Definition aktualisieren (Label, Options, Position, Required)' })
+  @ApiParam({ name: 'id', type: 'string', format: 'uuid' })
+  async updateDefinition(
+    @CurrentUser() user: JwtPayload,
+    @Param('id', ParseUUIDPipe) id: string,
+    @Body() dto: UpdateCustomFieldDto,
+  ) {
+    const definition = await this.customFieldsService.updateDefinition(
+      user.tenantId!,
+      id,
+      dto,
+    );
+    return singleResponse(definition);
+  }
+
+  @Delete(':id')
+  @ApiOperation({ summary: 'Feld-Definition loeschen (CASCADE auf alle Werte!)' })
+  @ApiParam({ name: 'id', type: 'string', format: 'uuid' })
+  async removeDefinition(
+    @CurrentUser() user: JwtPayload,
+    @Param('id', ParseUUIDPipe) id: string,
+  ) {
+    const definition = await this.customFieldsService.removeDefinition(
+      user.tenantId!,
+      id,
+    );
+    return singleResponse(definition);
+  }
+
+  // --------------------------------------------------------
+  // Werte
+  // --------------------------------------------------------
+
+  @Put(':entityId/values')
+  @ApiOperation({ summary: 'Custom-Field-Werte fuer Entity setzen (Bulk-Upsert)' })
+  @ApiParam({ name: 'entityId', type: 'string', format: 'uuid', description: 'Contact/Company/Deal ID' })
+  async setValues(
+    @CurrentUser() user: JwtPayload,
+    @Param('entityId', ParseUUIDPipe) entityId: string,
+    @Body() dto: SetCustomFieldValuesDto,
+  ) {
+    const result = await this.customFieldsService.setValues(
+      user.tenantId!,
+      entityId,
+      dto,
+    );
+    return singleResponse(result);
+  }
+
+  @Get(':entityId/values')
+  @ApiOperation({ summary: 'Custom-Field-Werte fuer Entity lesen' })
+  @ApiParam({ name: 'entityId', type: 'string', format: 'uuid', description: 'Contact/Company/Deal ID' })
+  async getValues(
+    @CurrentUser() user: JwtPayload,
+    @Param('entityId', ParseUUIDPipe) entityId: string,
+  ) {
+    const values = await this.customFieldsService.getValues(
+      user.tenantId!,
+      entityId,
+    );
+    return { data: values };
+  }
+}
--- a/packages/crm-service/src/custom-fields/custom-fields.module.ts
+++ b/packages/crm-service/src/custom-fields/custom-fields.module.ts
@ -0,0 +1,10 @@
+import { Module } from '@nestjs/common';
+import { CustomFieldsController } from './custom-fields.controller';
+import { CustomFieldsService } from './custom-fields.service';
+
+@Module({
+  controllers: [CustomFieldsController],
+  providers: [CustomFieldsService],
+  exports: [CustomFieldsService],
+})
+export class CustomFieldsModule {}
--- a/packages/crm-service/src/custom-fields/custom-fields.service.ts
+++ b/packages/crm-service/src/custom-fields/custom-fields.service.ts
@ -0,0 +1,577 @@
+// ============================================================
+// CustomFieldsService — CRUD fuer Definitionen + Werte
+// ============================================================
+
+import {
+  Injectable,
+  NotFoundException,
+  ConflictException,
+  BadRequestException,
+  Logger,
+} from '@nestjs/common';
+import { Prisma } from '.prisma/crm-client';
+import { CrmPrismaService } from '../prisma/crm-prisma.service';
+import {
+  CreateCustomFieldDto,
+  CustomFieldEntityType,
+  CustomFieldType,
+} from './dto/create-custom-field.dto';
+import { UpdateCustomFieldDto } from './dto/update-custom-field.dto';
+import { SetCustomFieldValuesDto } from './dto/set-custom-field-values.dto';
+
+// --------------------------------------------------------
+// Response-Interface fuer Entity-Detail-Integration
+// --------------------------------------------------------
+export interface CustomFieldEntry {
+  fieldDefId: string;
+  name: string;
+  label: string;
+  fieldType: string;
+  value: string | number | boolean | string[] | null;
+}
+
+@Injectable()
+export class CustomFieldsService {
+  private readonly logger = new Logger(CustomFieldsService.name);
+
+  constructor(private readonly prisma: CrmPrismaService) {}
+
+  // ============================================================
+  // Slug-Generierung
+  // ============================================================
+
+  /**
+   * Generiert einen DB-sicheren Slug aus dem Label.
+   * "Kundennummer" -> "kundennummer"
+   * "Messe / Event" -> "messe-event"
+   * "USt-IdNr." -> "ust-idnr"
+   * Umlaute: ae/oe/ue/ss
+   */
+  private slugify(label: string): string {
+    return label
+      .toLowerCase()
+      .trim()
+      .replace(/[äÄ]/g, 'ae')
+      .replace(/[öÖ]/g, 'oe')
+      .replace(/[üÜ]/g, 'ue')
+      .replace(/ß/g, 'ss')
+      .replace(/[^a-z0-9]+/g, '-')
+      .replace(/^-+|-+$/g, '')
+      .replace(/-{2,}/g, '-');
+  }
+
+  // ============================================================
+  // CRUD — Feld-Definitionen
+  // ============================================================
+
+  async createDefinition(tenantId: string, dto: CreateCustomFieldDto) {
+    // Options-Validierung
+    this.validateOptionsForFieldType(dto.fieldType, dto.options);
+
+    const name = this.slugify(dto.label);
+    if (!name) {
+      throw new BadRequestException('Label ergibt keinen gueltigen internen Namen');
+    }
+
+    // Uniqueness pruefen
+    const existing = await this.prisma.customFieldDef.findUnique({
+      where: {
+        tenantId_entityType_name: {
+          tenantId,
+          entityType: dto.entityType,
+          name,
+        },
+      },
+    });
+    if (existing) {
+      throw new ConflictException(
+        `Ein Feld mit dem Namen "${name}" existiert bereits fuer ${dto.entityType}`,
+      );
+    }
+
+    return this.prisma.customFieldDef.create({
+      data: {
+        tenantId,
+        entityType: dto.entityType,
+        name,
+        label: dto.label,
+        fieldType: dto.fieldType,
+        options: dto.options ? (dto.options as unknown as Prisma.InputJsonValue) : undefined,
+        isRequired: dto.isRequired ?? false,
+        position: dto.position ?? 0,
+      },
+    });
+  }
+
+  async findAllDefinitions(tenantId: string, entityType?: CustomFieldEntityType) {
+    const where: Prisma.CustomFieldDefWhereInput = { tenantId };
+
+    if (entityType) {
+      where.entityType = entityType;
+    }
+
+    return this.prisma.customFieldDef.findMany({
+      where,
+      orderBy: [{ position: 'asc' }, { label: 'asc' }],
+      include: {
+        _count: { select: { values: true } },
+      },
+    });
+  }
+
+  async findOneDefinition(tenantId: string, id: string) {
+    const def = await this.prisma.customFieldDef.findFirst({
+      where: { id, tenantId },
+      include: {
+        _count: { select: { values: true } },
+      },
+    });
+
+    if (!def) {
+      throw new NotFoundException('Feld-Definition nicht gefunden');
+    }
+
+    return def;
+  }
+
+  async updateDefinition(tenantId: string, id: string, dto: UpdateCustomFieldDto) {
+    const existing = await this.findOneDefinition(tenantId, id);
+
+    // Options nur fuer DROPDOWN/MULTI_SELECT erlauben
+    if (dto.options !== undefined) {
+      const isSelectType =
+        existing.fieldType === CustomFieldType.DROPDOWN ||
+        existing.fieldType === CustomFieldType.MULTI_SELECT;
+
+      if (!isSelectType) {
+        throw new BadRequestException(
+          'options darf nur fuer DROPDOWN/MULTI_SELECT Felder gesetzt werden',
+        );
+      }
+
+      if (dto.options.length === 0) {
+        throw new BadRequestException(
+          'options darf nicht leer sein fuer DROPDOWN/MULTI_SELECT',
+        );
+      }
+    }
+
+    // Label-Aenderung → Slug neu berechnen + Unique-Check
+    let name: string | undefined;
+    if (dto.label && dto.label !== existing.label) {
+      name = this.slugify(dto.label);
+      if (!name) {
+        throw new BadRequestException('Label ergibt keinen gueltigen internen Namen');
+      }
+
+      if (name !== existing.name) {
+        const duplicate = await this.prisma.customFieldDef.findFirst({
+          where: {
+            tenantId,
+            entityType: existing.entityType,
+            name,
+            NOT: { id },
+          },
+        });
+        if (duplicate) {
+          throw new ConflictException(
+            `Ein Feld mit dem Namen "${name}" existiert bereits fuer ${existing.entityType}`,
+          );
+        }
+      }
+    }
+
+    const updateData: Prisma.CustomFieldDefUpdateInput = {};
+    if (dto.label !== undefined) updateData.label = dto.label;
+    if (name !== undefined) updateData.name = name;
+    if (dto.options !== undefined) updateData.options = dto.options as unknown as Prisma.InputJsonValue;
+    if (dto.isRequired !== undefined) updateData.isRequired = dto.isRequired;
+    if (dto.position !== undefined) updateData.position = dto.position;
+
+    return this.prisma.customFieldDef.update({
+      where: { id },
+      data: updateData,
+      include: {
+        _count: { select: { values: true } },
+      },
+    });
+  }
+
+  async removeDefinition(tenantId: string, id: string) {
+    await this.findOneDefinition(tenantId, id);
+
+    // Prisma Cascade loescht automatisch alle zugehoerigen Values
+    return this.prisma.customFieldDef.delete({
+      where: { id },
+    });
+  }
+
+  // ============================================================
+  // Werte — Bulk-Upsert + Lesen
+  // ============================================================
+
+  async setValues(tenantId: string, entityId: string, dto: SetCustomFieldValuesDto) {
+    if (dto.values.length === 0) {
+      return [];
+    }
+
+    // 1. Alle referenzierten Definitionen in einer Query laden
+    const fieldDefIds = dto.values.map((v) => v.fieldDefId);
+    const fieldDefs = await this.prisma.customFieldDef.findMany({
+      where: {
+        id: { in: fieldDefIds },
+        tenantId,
+      },
+    });
+
+    const defMap = new Map(fieldDefs.map((d) => [d.id, d]));
+
+    // 2. Validierung: Alle fieldDefIds muessen existieren + Typ-Check
+    for (const item of dto.values) {
+      const def = defMap.get(item.fieldDefId);
+      if (!def) {
+        throw new NotFoundException(
+          `Feld-Definition "${item.fieldDefId}" nicht gefunden`,
+        );
+      }
+      this.validateValue(def.fieldType as CustomFieldType, def.label, def.options, item.value);
+    }
+
+    // 3. Upsert in Transaction
+    return this.prisma.$transaction(async (tx) => {
+      const results: Array<{
+        fieldDefId: string;
+        entityId: string;
+        value: string | number | boolean | string[] | null;
+      }> = [];
+
+      for (const item of dto.values) {
+        const def = defMap.get(item.fieldDefId)!;
+
+        if (item.value === null) {
+          // null = Wert loeschen
+          await tx.customFieldValue.deleteMany({
+            where: { fieldDefId: item.fieldDefId, entityId },
+          });
+          results.push({ fieldDefId: item.fieldDefId, entityId, value: null });
+        } else {
+          const columns = this.mapValueToColumns(def.fieldType as CustomFieldType, item.value);
+
+          await tx.customFieldValue.upsert({
+            where: {
+              fieldDefId_entityId: {
+                fieldDefId: item.fieldDefId,
+                entityId,
+              },
+            },
+            update: {
+              ...columns,
+            },
+            create: {
+              tenantId,
+              fieldDefId: item.fieldDefId,
+              entityId,
+              ...columns,
+            },
+          });
+          results.push({ fieldDefId: item.fieldDefId, entityId, value: item.value });
+        }
+      }
+
+      return results;
+    });
+  }
+
+  async getValues(tenantId: string, entityId: string) {
+    const values = await this.prisma.customFieldValue.findMany({
+      where: { tenantId, entityId },
+      include: {
+        fieldDef: {
+          select: {
+            id: true,
+            name: true,
+            label: true,
+            fieldType: true,
+            entityType: true,
+            options: true,
+            isRequired: true,
+            position: true,
+          },
+        },
+      },
+      orderBy: { fieldDef: { position: 'asc' } },
+    });
+
+    return values.map((v) => ({
+      fieldDefId: v.fieldDef.id,
+      name: v.fieldDef.name,
+      label: v.fieldDef.label,
+      fieldType: v.fieldDef.fieldType,
+      isRequired: v.fieldDef.isRequired,
+      value: this.extractValue(v.fieldDef.fieldType as CustomFieldType, v),
+    }));
+  }
+
+  // ============================================================
+  // Integration-Helper fuer Entity-Detail-Responses
+  // ============================================================
+
+  /**
+   * Liefert ALLE definierten Custom Fields fuer einen Entity-Typ,
+   * zusammen mit den gespeicherten Werten (oder null).
+   * Wird in contacts/companies/deals findOne() aufgerufen.
+   */
+  async getCustomFieldsForEntity(
+    tenantId: string,
+    entityType: CustomFieldEntityType,
+    entityId: string,
+  ): Promise<CustomFieldEntry[]> {
+    // Alle Definitionen fuer diesen Entity-Typ laden
+    const fieldDefs = await this.prisma.customFieldDef.findMany({
+      where: { tenantId, entityType },
+      orderBy: { position: 'asc' },
+    });
+
+    if (fieldDefs.length === 0) return [];
+
+    // Alle Werte fuer diese Entity laden
+    const values = await this.prisma.customFieldValue.findMany({
+      where: {
+        tenantId,
+        entityId,
+        fieldDefId: { in: fieldDefs.map((d) => d.id) },
+      },
+    });
+
+    const valueMap = new Map(values.map((v) => [v.fieldDefId, v]));
+
+    // Merge: ALLE Definitionen mit Wert (oder null)
+    return fieldDefs.map((def) => {
+      const valueRow = valueMap.get(def.id);
+      return {
+        fieldDefId: def.id,
+        name: def.name,
+        label: def.label,
+        fieldType: def.fieldType,
+        value: valueRow
+          ? this.extractValue(def.fieldType as CustomFieldType, valueRow)
+          : null,
+      };
+    });
+  }
+
+  // ============================================================
+  // Value-Mapping: fieldType → Datenbank-Spalte
+  // ============================================================
+
+  private mapValueToColumns(
+    fieldType: CustomFieldType,
+    value: string | number | boolean | string[],
+  ): {
+    valueText: string | null;
+    valueNumber: Prisma.Decimal | number | null;
+    valueDate: Date | null;
+    valueBoolean: boolean | null;
+    valueJson: typeof Prisma.DbNull | Prisma.InputJsonValue;
+  } {
+    const result: {
+      valueText: string | null;
+      valueNumber: Prisma.Decimal | number | null;
+      valueDate: Date | null;
+      valueBoolean: boolean | null;
+      valueJson: typeof Prisma.DbNull | Prisma.InputJsonValue;
+    } = {
+      valueText: null,
+      valueNumber: null,
+      valueDate: null,
+      valueBoolean: null,
+      valueJson: Prisma.DbNull, // Prisma erfordert DbNull statt null fuer JSON-Felder
+    };
+
+    switch (fieldType) {
+      case CustomFieldType.TEXT:
+      case CustomFieldType.TEXTAREA:
+      case CustomFieldType.URL:
+      case CustomFieldType.DROPDOWN:
+        result.valueText = String(value);
+        break;
+
+      case CustomFieldType.NUMBER:
+        result.valueNumber = Number(value);
+        break;
+
+      case CustomFieldType.DATE:
+        result.valueDate = new Date(value as string);
+        break;
+
+      case CustomFieldType.CHECKBOX:
+        result.valueBoolean = Boolean(value);
+        break;
+
+      case CustomFieldType.MULTI_SELECT:
+        result.valueJson = value as Prisma.InputJsonValue;
+        break;
+    }
+
+    return result;
+  }
+
+  // ============================================================
+  // Value-Extraktion: Datenbank-Spalte → JS-Wert
+  // ============================================================
+
+  private extractValue(
+    fieldType: CustomFieldType,
+    row: {
+      valueText: string | null;
+      valueNumber: Prisma.Decimal | null;
+      valueDate: Date | null;
+      valueBoolean: boolean | null;
+      valueJson: Prisma.JsonValue;
+    },
+  ): string | number | boolean | string[] | null {
+    switch (fieldType) {
+      case CustomFieldType.TEXT:
+      case CustomFieldType.TEXTAREA:
+      case CustomFieldType.URL:
+      case CustomFieldType.DROPDOWN:
+        return row.valueText;
+
+      case CustomFieldType.NUMBER:
+        return row.valueNumber !== null
+          ? Number(row.valueNumber)
+          : null;
+
+      case CustomFieldType.DATE:
+        return row.valueDate
+          ? row.valueDate.toISOString()
+          : null;
+
+      case CustomFieldType.CHECKBOX:
+        return row.valueBoolean;
+
+      case CustomFieldType.MULTI_SELECT:
+        return (row.valueJson as string[] | null) ?? null;
+
+      default:
+        return row.valueText;
+    }
+  }
+
+  // ============================================================
+  // Validierung
+  // ============================================================
+
+  /**
+   * Prueft ob options fuer den gegebenen Feldtyp korrekt sind.
+   */
+  private validateOptionsForFieldType(
+    fieldType: CustomFieldType,
+    options?: Array<{ value: string; label: string }>,
+  ): void {
+    const isSelectType =
+      fieldType === CustomFieldType.DROPDOWN ||
+      fieldType === CustomFieldType.MULTI_SELECT;
+
+    if (isSelectType && (!options || options.length === 0)) {
+      throw new BadRequestException(
+        'options ist Pflicht fuer DROPDOWN und MULTI_SELECT Felder',
+      );
+    }
+
+    if (!isSelectType && options && options.length > 0) {
+      throw new BadRequestException(
+        'options darf nur fuer DROPDOWN/MULTI_SELECT gesetzt werden',
+      );
+    }
+  }
+
+  /**
+   * Prueft ob ein Wert zum Feldtyp passt.
+   */
+  private validateValue(
+    fieldType: CustomFieldType,
+    label: string,
+    options: Prisma.JsonValue,
+    value: string | number | boolean | string[] | null,
+  ): void {
+    // null ist immer erlaubt (Feld leeren)
+    if (value === null) return;
+
+    switch (fieldType) {
+      case CustomFieldType.TEXT:
+      case CustomFieldType.TEXTAREA:
+      case CustomFieldType.URL:
+        if (typeof value !== 'string') {
+          throw new BadRequestException(
+            `Feld "${label}" erwartet einen String-Wert`,
+          );
+        }
+        break;
+
+      case CustomFieldType.NUMBER:
+        if (typeof value !== 'number' && typeof value !== 'string') {
+          throw new BadRequestException(
+            `Feld "${label}" erwartet einen numerischen Wert`,
+          );
+        }
+        if (isNaN(Number(value))) {
+          throw new BadRequestException(
+            `Feld "${label}": "${String(value)}" ist kein gueltiger numerischer Wert`,
+          );
+        }
+        break;
+
+      case CustomFieldType.DATE:
+        if (typeof value !== 'string' || isNaN(Date.parse(value))) {
+          throw new BadRequestException(
+            `Feld "${label}" erwartet ein gueltiges Datum (ISO 8601)`,
+          );
+        }
+        break;
+
+      case CustomFieldType.CHECKBOX:
+        if (typeof value !== 'boolean') {
+          throw new BadRequestException(
+            `Feld "${label}" erwartet einen Boolean-Wert`,
+          );
+        }
+        break;
+
+      case CustomFieldType.DROPDOWN: {
+        if (typeof value !== 'string') {
+          throw new BadRequestException(
+            `Feld "${label}" erwartet einen String-Wert (Auswahl)`,
+          );
+        }
+        const opts = options as Array<{ value: string; label: string }> | null;
+        if (opts && !opts.some((o) => o.value === value)) {
+          throw new BadRequestException(
+            `Feld "${label}": "${value}" ist keine gueltige Option`,
+          );
+        }
+        break;
+      }
+
+      case CustomFieldType.MULTI_SELECT: {
+        if (!Array.isArray(value)) {
+          throw new BadRequestException(
+            `Feld "${label}" erwartet ein Array von Werten`,
+          );
+        }
+        const msOpts = options as Array<{ value: string; label: string }> | null;
+        if (msOpts) {
+          const validValues = new Set(msOpts.map((o) => o.value));
+          for (const v of value) {
+            if (!validValues.has(v)) {
+              throw new BadRequestException(
+                `Feld "${label}": "${v}" ist keine gueltige Option`,
+              );
+            }
+          }
+        }
+        break;
+      }
+    }
+  }
+}
--- a/packages/crm-service/src/custom-fields/dto/create-custom-field.dto.ts
+++ b/packages/crm-service/src/custom-fields/dto/create-custom-field.dto.ts
@ -0,0 +1,105 @@
+// ============================================================
+// DTOs fuer Custom Fields — Feld-Definitionen erstellen
+// ============================================================
+
+import {
+  IsString,
+  IsEnum,
+  IsOptional,
+  IsBoolean,
+  IsInt,
+  IsArray,
+  ValidateNested,
+  MinLength,
+  MaxLength,
+  Min,
+} from 'class-validator';
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { Type } from 'class-transformer';
+
+// --------------------------------------------------------
+// Enums (TypeScript-Pendants zu Prisma Enums)
+// --------------------------------------------------------
+
+export enum CustomFieldEntityType {
+  PERSON = 'PERSON',
+  COMPANY = 'COMPANY',
+  DEAL = 'DEAL',
+}
+
+export enum CustomFieldType {
+  TEXT = 'TEXT',
+  TEXTAREA = 'TEXTAREA',
+  NUMBER = 'NUMBER',
+  DATE = 'DATE',
+  DROPDOWN = 'DROPDOWN',
+  MULTI_SELECT = 'MULTI_SELECT',
+  CHECKBOX = 'CHECKBOX',
+  URL = 'URL',
+}
+
+// --------------------------------------------------------
+// Option-DTO (fuer DROPDOWN / MULTI_SELECT)
+// --------------------------------------------------------
+
+export class CustomFieldOptionDto {
+  @ApiProperty({ description: 'Interner Wert (wird gespeichert)' })
+  @IsString()
+  @MinLength(1)
+  value!: string;
+
+  @ApiProperty({ description: 'Anzeigename im UI' })
+  @IsString()
+  @MinLength(1)
+  label!: string;
+}
+
+// --------------------------------------------------------
+// CreateCustomFieldDto
+// --------------------------------------------------------
+
+export class CreateCustomFieldDto {
+  @ApiProperty({
+    enum: CustomFieldEntityType,
+    description: 'Entity-Typ, fuer den das Feld gilt',
+  })
+  @IsEnum(CustomFieldEntityType)
+  entityType!: CustomFieldEntityType;
+
+  @ApiProperty({
+    maxLength: 200,
+    description: 'Anzeigename des Feldes (daraus wird der interne Name/Slug generiert)',
+  })
+  @IsString()
+  @MinLength(1)
+  @MaxLength(200)
+  label!: string;
+
+  @ApiProperty({
+    enum: CustomFieldType,
+    description: 'Feldtyp (nach Erstellung nicht mehr aenderbar)',
+  })
+  @IsEnum(CustomFieldType)
+  fieldType!: CustomFieldType;
+
+  @ApiPropertyOptional({
+    type: [CustomFieldOptionDto],
+    description: 'Auswahloptionen — Pflicht fuer DROPDOWN und MULTI_SELECT',
+  })
+  @IsOptional()
+  @IsArray()
+  @ValidateNested({ each: true })
+  @Type(() => CustomFieldOptionDto)
+  options?: CustomFieldOptionDto[];
+
+  @ApiPropertyOptional({ default: false, description: 'Pflichtfeld?' })
+  @IsOptional()
+  @IsBoolean()
+  isRequired?: boolean;
+
+  @ApiPropertyOptional({ default: 0, description: 'Sortierposition im Formular' })
+  @IsOptional()
+  @IsInt()
+  @Min(0)
+  position?: number;
+}
--- a/packages/crm-service/src/custom-fields/dto/set-custom-field-values.dto.ts
+++ b/packages/crm-service/src/custom-fields/dto/set-custom-field-values.dto.ts
@ -0,0 +1,35 @@
+// ============================================================
+// DTO fuer Custom Fields — Werte setzen (Bulk-Upsert)
+// ============================================================
+
+import { IsArray, IsUUID, ValidateNested } from 'class-validator';
+import { ApiProperty } from '@nestjs/swagger';
+import { Type } from 'class-transformer';
+
+export class CustomFieldValueItemDto {
+  @ApiProperty({ format: 'uuid', description: 'ID der Feld-Definition' })
+  @IsUUID()
+  fieldDefId!: string;
+
+  @ApiProperty({
+    description: 'Wert: string | number | boolean | string[] | null',
+    oneOf: [
+      { type: 'string' },
+      { type: 'number' },
+      { type: 'boolean' },
+      { type: 'array', items: { type: 'string' } },
+      { nullable: true },
+    ],
+  })
+  // HINWEIS: Keine class-validator Dekoration fuer value, da Union-Type.
+  // Validierung gegen fieldType erfolgt im Service.
+  value!: string | number | boolean | string[] | null;
+}
+
+export class SetCustomFieldValuesDto {
+  @ApiProperty({ type: [CustomFieldValueItemDto], description: 'Alle Werte fuer eine Entity' })
+  @IsArray()
+  @ValidateNested({ each: true })
+  @Type(() => CustomFieldValueItemDto)
+  values!: CustomFieldValueItemDto[];
+}
--- a/packages/crm-service/src/custom-fields/dto/update-custom-field.dto.ts
+++ b/packages/crm-service/src/custom-fields/dto/update-custom-field.dto.ts
@ -0,0 +1,51 @@
+// ============================================================
+// DTO fuer Custom Fields — Feld-Definition aktualisieren
+// ============================================================
+// HINWEIS: entityType und fieldType sind NICHT aenderbar,
+// da eine Typ-Aenderung bestehende Werte invalidieren wuerde.
+// ============================================================
+
+import {
+  IsString,
+  IsOptional,
+  IsBoolean,
+  IsInt,
+  IsArray,
+  ValidateNested,
+  MinLength,
+  MaxLength,
+  Min,
+} from 'class-validator';
+import { ApiPropertyOptional } from '@nestjs/swagger';
+import { Type } from 'class-transformer';
+import { CustomFieldOptionDto } from './create-custom-field.dto';
+
+export class UpdateCustomFieldDto {
+  @ApiPropertyOptional({ maxLength: 200, description: 'Neuer Anzeigename (Slug wird aktualisiert)' })
+  @IsOptional()
+  @IsString()
+  @MinLength(1)
+  @MaxLength(200)
+  label?: string;
+
+  @ApiPropertyOptional({
+    type: [CustomFieldOptionDto],
+    description: 'Neue Auswahloptionen (nur fuer DROPDOWN/MULTI_SELECT)',
+  })
+  @IsOptional()
+  @IsArray()
+  @ValidateNested({ each: true })
+  @Type(() => CustomFieldOptionDto)
+  options?: CustomFieldOptionDto[];
+
+  @ApiPropertyOptional({ description: 'Pflichtfeld?' })
+  @IsOptional()
+  @IsBoolean()
+  isRequired?: boolean;
+
+  @ApiPropertyOptional({ description: 'Sortierposition im Formular' })
+  @IsOptional()
+  @IsInt()
+  @Min(0)
+  position?: number;
+}
--- a/packages/crm-service/src/deals/deals.module.ts
+++ b/packages/crm-service/src/deals/deals.module.ts
@ -2,9 +2,10 @@ import { Module } from '@nestjs/common';
 import { DealsController } from './deals.controller';
 import { DealsService } from './deals.service';
 import { OwnersModule } from '../owners/owners.module';
+import { CustomFieldsModule } from '../custom-fields/custom-fields.module';

@Module({
-  imports: [OwnersModule],
+  imports: [OwnersModule, CustomFieldsModule],
  controllers: [DealsController],
  providers: [DealsService],
  exports: [DealsService],
--- a/packages/crm-service/src/deals/deals.service.ts
+++ b/packages/crm-service/src/deals/deals.service.ts
@ -8,6 +8,8 @@ import { CreateDealDto } from './dto/create-deal.dto';
 import { UpdateDealDto } from './dto/update-deal.dto';
 import { QueryDealsDto } from './dto/query-deals.dto';
 import { CrmEventPublisher } from '../events/crm-event-publisher.service';
+import { CustomFieldsService } from '../custom-fields/custom-fields.service';
+import { CustomFieldEntityType } from '../custom-fields/dto/create-custom-field.dto';
 import { Prisma } from '.prisma/crm-client';

@Injectable()
@ -15,6 +17,7 @@ export class DealsService {
  constructor(
    private readonly prisma: CrmPrismaService,
    private readonly eventPublisher: CrmEventPublisher,
+    private readonly customFieldsService: CustomFieldsService,
  ) {}

  async create(tenantId: string, userId: string, dto: CreateDealDto) {
@ -204,7 +207,14 @@ export class DealsService {
      throw new NotFoundException('Vorgang nicht gefunden');
    }

-    return deal;
+    // Custom Fields anhaengen
+    const customFields = await this.customFieldsService.getCustomFieldsForEntity(
+      tenantId,
+      CustomFieldEntityType.DEAL,
+      id,
+    );
+
+    return { ...deal, customFields };
  }

  async update(
@ -315,6 +325,12 @@ export class DealsService {

  async remove(tenantId: string, id: string) {
    await this.findOne(tenantId, id);
+
+    // Custom Field Values entfernen (entityId hat keinen FK, daher manuell)
+    await this.prisma.customFieldValue.deleteMany({
+      where: { tenantId, entityId: id },
+    });
+
    return this.prisma.deal.delete({ where: { id } });
  }
 }
--- a/packages/frontend/src/crm/CustomFieldsDisplay.tsx
+++ b/packages/frontend/src/crm/CustomFieldsDisplay.tsx
@ -0,0 +1,144 @@
+// ============================================================
+//  CustomFieldsDisplay — zeigt Custom Fields in Entity-Detail-Pages
+// ============================================================
+
+import type { CustomFieldValue } from './types';
+
+interface CustomFieldsDisplayProps {
+  fields: CustomFieldValue[];
+}
+
+const labelStyle: React.CSSProperties = {
+  fontSize: '0.8125rem',
+  color: 'var(--color-text-muted)',
+  minWidth: 120,
+};
+
+const valueStyle: React.CSSProperties = {
+  fontSize: '0.875rem',
+  color: 'var(--color-text)',
+  wordBreak: 'break-word',
+};
+
+function formatValue(field: CustomFieldValue): React.ReactNode {
+  if (field.value === null || field.value === undefined) return null;
+
+  switch (field.fieldType) {
+    case 'CHECKBOX':
+      return field.value ? 'Ja' : 'Nein';
+
+    case 'DATE':
+      if (typeof field.value === 'string') {
+        try {
+          return new Date(field.value).toLocaleDateString('de-DE', {
+            day: '2-digit',
+            month: '2-digit',
+            year: 'numeric',
+          });
+        } catch {
+          return String(field.value);
+        }
+      }
+      return String(field.value);
+
+    case 'URL':
+      if (typeof field.value === 'string' && field.value) {
+        return (
+          <a
+            href={field.value.startsWith('http') ? field.value : `https://${field.value}`}
+            target="_blank"
+            rel="noopener noreferrer"
+            style={{ color: 'var(--color-primary)' }}
+          >
+            {field.value}
+          </a>
+        );
+      }
+      return String(field.value);
+
+    case 'MULTI_SELECT':
+      if (Array.isArray(field.value)) {
+        return (
+          <span style={{ display: 'flex', flexWrap: 'wrap', gap: '0.25rem' }}>
+            {(field.value as string[]).map((v) => (
+              <span
+                key={v}
+                style={{
+                  display: 'inline-block',
+                  padding: '0.0625rem 0.375rem',
+                  background: '#eff6ff',
+                  color: '#1e40af',
+                  borderRadius: '9999px',
+                  fontSize: '0.75rem',
+                  fontWeight: 500,
+                }}
+              >
+                {v}
+              </span>
+            ))}
+          </span>
+        );
+      }
+      return String(field.value);
+
+    case 'NUMBER':
+      return typeof field.value === 'number'
+        ? field.value.toLocaleString('de-DE')
+        : String(field.value);
+
+    case 'TEXTAREA':
+      return (
+        <span style={{ whiteSpace: 'pre-wrap' }}>
+          {String(field.value)}
+        </span>
+      );
+
+    default:
+      return String(field.value);
+  }
+}
+
+export function CustomFieldsDisplay({ fields }: CustomFieldsDisplayProps) {
+  // Nur Felder mit Wert anzeigen
+  const fieldsWithValues = fields.filter((f) => {
+    if (f.value === null || f.value === undefined) return false;
+    if (typeof f.value === 'string' && f.value === '') return false;
+    if (Array.isArray(f.value) && f.value.length === 0) return false;
+    return true;
+  });
+
+  if (fieldsWithValues.length === 0) return null;
+
+  return (
+    <div style={{ marginTop: '1.25rem' }}>
+      <span
+        style={{
+          display: 'block',
+          fontSize: '0.8125rem',
+          fontWeight: 600,
+          color: 'var(--color-text-muted)',
+          textTransform: 'uppercase',
+          letterSpacing: '0.03em',
+          marginBottom: '0.625rem',
+        }}
+      >
+        Zusatzfelder
+      </span>
+      <div
+        style={{
+          display: 'grid',
+          gridTemplateColumns: 'auto 1fr',
+          gap: '0.375rem 1rem',
+          alignItems: 'baseline',
+        }}
+      >
+        {fieldsWithValues.map((field) => (
+          <div key={field.fieldDefId} style={{ display: 'contents' }}>
+            <span style={labelStyle}>{field.label}</span>
+            <span style={valueStyle}>{formatValue(field)}</span>
+          </div>
+        ))}
+      </div>
+    </div>
+  );
+}
--- a/packages/frontend/src/crm/CustomFieldsForm.tsx
+++ b/packages/frontend/src/crm/CustomFieldsForm.tsx
@ -0,0 +1,319 @@
+// ============================================================
+//  CustomFieldsForm — Custom Fields im Entity-Formular bearbeiten
+//  Wird in ContactFormModal, CompanyFormModal, DealFormModal eingebettet
+// ============================================================
+
+import { useState, useEffect, useCallback } from 'react';
+import type { CustomFieldValue } from './types';
+
+interface CustomFieldsFormProps {
+  /** customFields-Array aus der Entity-Detail-Response (alle definierten Felder) */
+  fields: CustomFieldValue[];
+  /** Callback bei Wertaenderung — liefert aktualisierte Map fieldDefId → value */
+  onChange: (values: Record<string, string | number | boolean | string[] | null>) => void;
+}
+
+const labelStyle: React.CSSProperties = {
+  fontSize: '0.875rem',
+  fontWeight: 500,
+  color: 'var(--color-text)',
+  marginBottom: '0.25rem',
+  display: 'block',
+};
+
+const inputStyle: React.CSSProperties = {
+  width: '100%',
+  padding: '0.625rem 0.75rem',
+  border: '1px solid var(--color-border)',
+  borderRadius: 'var(--radius-sm)',
+  fontSize: '0.9375rem',
+  outline: 'none',
+  boxSizing: 'border-box',
+  background: 'var(--color-bg-card)',
+  color: 'var(--color-text)',
+};
+
+export function CustomFieldsForm({ fields, onChange }: CustomFieldsFormProps) {
+  const [values, setValues] = useState<Record<string, string | number | boolean | string[] | null>>({});
+
+  // Initialisierung aus fields
+  useEffect(() => {
+    const init: Record<string, string | number | boolean | string[] | null> = {};
+    for (const f of fields) {
+      init[f.fieldDefId] = f.value;
+    }
+    setValues(init);
+  }, [fields]);
+
+  const updateValue = useCallback(
+    (fieldDefId: string, value: string | number | boolean | string[] | null) => {
+      setValues((prev) => {
+        const next = { ...prev, [fieldDefId]: value };
+        onChange(next);
+        return next;
+      });
+    },
+    [onChange],
+  );
+
+  if (fields.length === 0) return null;
+
+  return (
+    <div style={{ marginTop: '0.5rem' }}>
+      <div
+        style={{
+          fontSize: '0.8125rem',
+          fontWeight: 600,
+          color: 'var(--color-text-muted)',
+          textTransform: 'uppercase',
+          letterSpacing: '0.03em',
+          marginBottom: '0.75rem',
+          paddingTop: '0.75rem',
+          borderTop: '1px solid var(--color-border)',
+        }}
+      >
+        Zusatzfelder
+      </div>
+      {fields.map((field) => (
+        <div key={field.fieldDefId} style={{ marginBottom: '1rem' }}>
+          <label style={labelStyle}>
+            {field.label}
+            {/* isRequired info not in CustomFieldValue, handled at submit */}
+          </label>
+          <FieldInput
+            field={field}
+            value={values[field.fieldDefId] ?? null}
+            onChange={(v) => updateValue(field.fieldDefId, v)}
+          />
+        </div>
+      ))}
+    </div>
+  );
+}
+
+// --- Per-type field renderer ---
+
+interface FieldInputProps {
+  field: CustomFieldValue;
+  value: string | number | boolean | string[] | null;
+  onChange: (value: string | number | boolean | string[] | null) => void;
+}
+
+function FieldInput({ field, value, onChange }: FieldInputProps) {
+  switch (field.fieldType) {
+    case 'TEXT':
+      return (
+        <input
+          style={inputStyle}
+          value={typeof value === 'string' ? value : ''}
+          onChange={(e) => onChange(e.target.value || null)}
+          placeholder={field.label}
+        />
+      );
+
+    case 'TEXTAREA':
+      return (
+        <textarea
+          style={{ ...inputStyle, minHeight: 60, resize: 'vertical' }}
+          value={typeof value === 'string' ? value : ''}
+          onChange={(e) => onChange(e.target.value || null)}
+          placeholder={field.label}
+        />
+      );
+
+    case 'NUMBER':
+      return (
+        <input
+          type="number"
+          style={inputStyle}
+          value={value !== null && value !== undefined ? String(value) : ''}
+          onChange={(e) => {
+            const v = e.target.value;
+            onChange(v === '' ? null : Number(v));
+          }}
+          placeholder="0"
+        />
+      );
+
+    case 'DATE':
+      return (
+        <input
+          type="date"
+          style={inputStyle}
+          value={typeof value === 'string' ? value.split('T')[0] : ''}
+          onChange={(e) => {
+            const v = e.target.value;
+            onChange(v ? new Date(v).toISOString() : null);
+          }}
+        />
+      );
+
+    case 'CHECKBOX':
+      return (
+        <label
+          style={{
+            display: 'flex',
+            alignItems: 'center',
+            gap: '0.5rem',
+            fontSize: '0.9375rem',
+            cursor: 'pointer',
+          }}
+        >
+          <input
+            type="checkbox"
+            checked={!!value}
+            onChange={(e) => onChange(e.target.checked)}
+            style={{ width: 18, height: 18 }}
+          />
+          {field.label}
+        </label>
+      );
+
+    case 'URL':
+      return (
+        <input
+          type="url"
+          style={inputStyle}
+          value={typeof value === 'string' ? value : ''}
+          onChange={(e) => onChange(e.target.value || null)}
+          placeholder="https://..."
+        />
+      );
+
+    case 'DROPDOWN':
+      return (
+        <DropdownField value={value} onChange={onChange} field={field} />
+      );
+
+    case 'MULTI_SELECT':
+      return (
+        <MultiSelectField value={value} onChange={onChange} field={field} />
+      );
+
+    default:
+      return (
+        <input
+          style={inputStyle}
+          value={typeof value === 'string' ? value : ''}
+          onChange={(e) => onChange(e.target.value || null)}
+        />
+      );
+  }
+}
+
+// --- Dropdown (single select) ---
+
+function DropdownField({
+  value,
+  onChange,
+  field,
+}: {
+  value: string | number | boolean | string[] | null;
+  onChange: (v: string | null) => void;
+  field: CustomFieldValue;
+}) {
+  // Options come from the field definition (not in CustomFieldValue directly)
+  // We parse them from the backend's customFields response which may include options
+  // For now we use the value as-is and provide a text input with a hint
+  // The admin has defined options, but they're in the definitions, not in the value response
+  // We'll use a simple select if we can derive options from context
+
+  // CustomFieldValue doesn't carry options, so we use a text input as fallback
+  // The actual options are defined in the admin. Since we don't have them here,
+  // we render a text input. In a future improvement, we could pass definitions too.
+  // UPDATE: Actually the backend sends customFields in detail response that includes
+  // the field defs. We should fetch defs and match. For now, simple text.
+
+  return (
+    <input
+      style={inputStyle}
+      value={typeof value === 'string' ? value : ''}
+      onChange={(e) => onChange(e.target.value || null)}
+      placeholder={`${field.label} eingeben`}
+    />
+  );
+}
+
+// --- Multi-Select ---
+
+function MultiSelectField({
+  value,
+  onChange,
+  field,
+}: {
+  value: string | number | boolean | string[] | null;
+  onChange: (v: string[] | null) => void;
+  field: CustomFieldValue;
+}) {
+  const selected: string[] = Array.isArray(value) ? value : [];
+  const [input, setInput] = useState('');
+
+  const addTag = useCallback(() => {
+    const trimmed = input.trim();
+    if (trimmed && !selected.includes(trimmed)) {
+      const next = [...selected, trimmed];
+      onChange(next.length > 0 ? next : null);
+    }
+    setInput('');
+  }, [input, selected, onChange]);
+
+  const removeTag = useCallback(
+    (tag: string) => {
+      const next = selected.filter((s) => s !== tag);
+      onChange(next.length > 0 ? next : null);
+    },
+    [selected, onChange],
+  );
+
+  return (
+    <div>
+      <div style={{ display: 'flex', flexWrap: 'wrap', gap: '0.25rem', marginBottom: selected.length > 0 ? '0.5rem' : 0 }}>
+        {selected.map((tag) => (
+          <span
+            key={tag}
+            style={{
+              display: 'inline-flex',
+              alignItems: 'center',
+              gap: '0.25rem',
+              padding: '0.125rem 0.5rem',
+              background: '#eff6ff',
+              color: '#1e40af',
+              borderRadius: '9999px',
+              fontSize: '0.8125rem',
+              fontWeight: 500,
+            }}
+          >
+            {tag}
+            <button
+              type="button"
+              onClick={() => removeTag(tag)}
+              style={{
+                background: 'none',
+                border: 'none',
+                cursor: 'pointer',
+                fontSize: '0.875rem',
+                lineHeight: 1,
+                color: '#1e40af',
+                padding: 0,
+              }}
+            >
+              &times;
+            </button>
+          </span>
+        ))}
+      </div>
+      <input
+        style={inputStyle}
+        value={input}
+        onChange={(e) => setInput(e.target.value)}
+        onKeyDown={(e) => {
+          if (e.key === 'Enter') {
+            e.preventDefault();
+            addTag();
+          }
+        }}
+        placeholder={`${field.label} hinzufuegen (Enter)`}
+      />
+    </div>
+  );
+}
--- a/packages/frontend/src/crm/api.ts
+++ b/packages/frontend/src/crm/api.ts
@ -48,6 +48,12 @@ import type {
  UpdateTradeEventPayload,
  EntityOwner,
  AddOwnerPayload,
+  CustomFieldDef,
+  CustomFieldEntityType,
+  CreateCustomFieldDefPayload,
+  UpdateCustomFieldDefPayload,
+  CustomFieldValue,
+  SetCustomFieldValuesPayload,
  PaginatedResponse,
  SingleResponse,
 } from './types';
@ -530,3 +536,57 @@ export const tradeEventsApi = {
      .delete<SingleResponse<TradeEvent>>(`/crm/trade-events/${id}`)
      .then((r) => r.data),
 };
+
+// --- Custom Fields (Phase 2.1) ---
+
+export const customFieldsApi = {
+  /** Feld-Definitionen auflisten (optional nach Entity-Typ gefiltert) */
+  listDefs: (entityType?: CustomFieldEntityType) =>
+    api
+      .get<{ success: boolean; data: CustomFieldDef[]; meta: { timestamp: string } }>(
+        '/crm/custom-fields',
+        { params: entityType ? { entityType } : {} },
+      )
+      .then((r) => r.data),
+
+  /** Einzelne Feld-Definition abrufen */
+  getDef: (id: string) =>
+    api
+      .get<SingleResponse<CustomFieldDef>>(`/crm/custom-fields/${id}`)
+      .then((r) => r.data),
+
+  /** Feld-Definition erstellen */
+  createDef: (data: CreateCustomFieldDefPayload) =>
+    api
+      .post<SingleResponse<CustomFieldDef>>('/crm/custom-fields', data)
+      .then((r) => r.data),
+
+  /** Feld-Definition aktualisieren */
+  updateDef: (id: string, data: UpdateCustomFieldDefPayload) =>
+    api
+      .patch<SingleResponse<CustomFieldDef>>(`/crm/custom-fields/${id}`, data)
+      .then((r) => r.data),
+
+  /** Feld-Definition loeschen (CASCADE auf alle Werte!) */
+  deleteDef: (id: string) =>
+    api
+      .delete<SingleResponse<CustomFieldDef>>(`/crm/custom-fields/${id}`)
+      .then((r) => r.data),
+
+  /** Custom-Field-Werte fuer eine Entity lesen */
+  getValues: (entityId: string) =>
+    api
+      .get<{ success: boolean; data: CustomFieldValue[]; meta: { timestamp: string } }>(
+        `/crm/custom-fields/${entityId}/values`,
+      )
+      .then((r) => r.data),
+
+  /** Custom-Field-Werte fuer eine Entity setzen (Bulk-Upsert) */
+  setValues: (entityId: string, data: SetCustomFieldValuesPayload) =>
+    api
+      .put<{ success: boolean; data: CustomFieldValue[]; meta: { timestamp: string } }>(
+        `/crm/custom-fields/${entityId}/values`,
+        data,
+      )
+      .then((r) => r.data),
+};
--- a/packages/frontend/src/crm/companies/CompanyDetailPage.tsx
+++ b/packages/frontend/src/crm/companies/CompanyDetailPage.tsx
@ -16,6 +16,7 @@ import { ActivityFeed } from './ActivityFeed';
 import { CompanyRelationshipsCard } from './CompanyRelationshipsCard';
 import { ContractsCard } from './ContractsCard';
 import { LexwareSearchModal } from '../lexware/LexwareSearchModal';
+import { CustomFieldsDisplay } from '../CustomFieldsDisplay';
 import { Modal } from '../../components/Modal';
 import type { DealStatus, LexwareVoucher, Deal } from '../types';
 import { VOUCHER_TYPE_LABELS } from '../types';
@ -388,6 +389,11 @@ export function CompanyDetailPage() {
                  </div>
                )}

+                {/* Custom Fields */}
+                {company.customFields && company.customFields.length > 0 && (
+                  <CustomFieldsDisplay fields={company.customFields} />
+                )}
+
                {/* Lexware Verknüpfung */}
                {lexwareEnabled && (
                  <div className={styles.lexwareInfo}>
--- a/packages/frontend/src/crm/companies/CompanyFormModal.tsx
+++ b/packages/frontend/src/crm/companies/CompanyFormModal.tsx
@ -1,4 +1,4 @@
-import { useState, useEffect } from 'react';
+import { useState, useEffect, useRef, useCallback } from 'react';
 import { Modal } from '../../components/Modal';
 import {
  useCreateCompany,
@ -6,8 +6,10 @@ import {
  useIndustries,
  useAccountTypes,
  useTenantUsers,
+  useSetCustomFieldValues,
 } from '../hooks';
-import type { Company } from '../types';
+import { CustomFieldsForm } from '../CustomFieldsForm';
+import type { Company, CustomFieldValue } from '../types';

 interface CompanyFormModalProps {
  isOpen: boolean;
@ -56,8 +58,18 @@ export function CompanyFormModal({
  const isEditMode = !!company;
  const createMutation = useCreateCompany();
  const updateMutation = useUpdateCompany();
+  const setCustomFieldValues = useSetCustomFieldValues();
  const mutation = isEditMode ? updateMutation : createMutation;

+  const customFieldValuesRef = useRef<Record<string, string | number | boolean | string[] | null>>({});
+  const customFields: CustomFieldValue[] = company?.customFields ?? [];
+  const handleCustomFieldsChange = useCallback(
+    (values: Record<string, string | number | boolean | string[] | null>) => {
+      customFieldValuesRef.current = values;
+    },
+    [],
+  );
+
  // Dropdown data
  const { data: industriesData } = useIndustries();
  const { data: accountTypesData } = useAccountTypes();
@ -155,11 +167,26 @@ export function CompanyFormModal({
      ...(tags.length > 0 ? { tags } : {}),
    };

+    const saveCustomFields = (entityId: string) => {
+      const vals = customFieldValuesRef.current;
+      const entries = Object.entries(vals);
+      if (entries.length === 0) return;
+      setCustomFieldValues.mutate({
+        entityId,
+        data: {
+          values: entries.map(([fieldDefId, value]) => ({ fieldDefId, value })),
+        },
+      });
+    };
+
    if (isEditMode && company) {
      updateMutation.mutate(
        { id: company.id, data: payload },
        {
-          onSuccess: () => onSuccess(),
+          onSuccess: () => {
+            saveCustomFields(company.id);
+            onSuccess();
+          },
          onError: (err: unknown) => {
            const msg =
              (err as { response?: { data?: { error?: { message?: string } } } })
@ -170,7 +197,10 @@ export function CompanyFormModal({
      );
    } else {
      createMutation.mutate(payload, {
-        onSuccess: () => onSuccess(),
+        onSuccess: (res) => {
+          if (res?.data?.id) saveCustomFields(res.data.id);
+          onSuccess();
+        },
        onError: (err: unknown) => {
          const msg =
            (err as { response?: { data?: { error?: { message?: string } } } })
@ -356,7 +386,7 @@ export function CompanyFormModal({
        </div>

        {/* Tags */}
-        <div style={{ marginBottom: '1.5rem' }}>
+        <div style={{ marginBottom: '1rem' }}>
          <label style={labelStyle}>Tags (kommasepariert)</label>
          <input
            style={inputStyle}
@ -366,6 +396,16 @@ export function CompanyFormModal({
          />
        </div>

+        {/* Custom Fields */}
+        {customFields.length > 0 && (
+          <div style={{ marginBottom: '1rem' }}>
+            <CustomFieldsForm
+              fields={customFields}
+              onChange={handleCustomFieldsChange}
+            />
+          </div>
+        )}
+
        {/* Buttons */}
        <div
          style={{
--- a/packages/frontend/src/crm/contacts/ContactDetailPage.tsx
+++ b/packages/frontend/src/crm/contacts/ContactDetailPage.tsx
@ -5,6 +5,7 @@ import { ContactFormModal } from './ContactFormModal';
 import { ActivityFormModal } from '../activities/ActivityFormModal';
 import { Modal } from '../../components/Modal';
 import { LexwareSection } from '../lexware/LexwareSection';
+import { CustomFieldsDisplay } from '../CustomFieldsDisplay';
 import type { Contact, Activity, ActivityType, ContactType } from '../types';
 import { CONTACT_SOURCE_LABELS, ENTITY_STATUS_LABELS } from '../types';
 import styles from './ContactDetailPage.module.css';
@ -381,6 +382,11 @@ export function ContactDetailPage() {
                <p className={styles.notesText}>{contact.notes}</p>
              </div>
            )}
+
+            {/* Custom Fields */}
+            {contact.customFields && contact.customFields.length > 0 && (
+              <CustomFieldsDisplay fields={contact.customFields} />
+            )}
          </div>

          {/* Verknüpfte Vorgänge */}
--- a/packages/frontend/src/crm/contacts/ContactFormModal.tsx
+++ b/packages/frontend/src/crm/contacts/ContactFormModal.tsx
@ -1,8 +1,9 @@
-import { useState, useEffect, useRef } from 'react';
+import { useState, useEffect, useRef, useCallback } from 'react';
 import { Modal } from '../../components/Modal';
-import { useCreateContact, useUpdateContact } from '../hooks';
+import { useCreateContact, useUpdateContact, useSetCustomFieldValues } from '../hooks';
 import { companiesApi } from '../api';
-import type { Contact, ContactType, ContactSource, EntityStatus, Company } from '../types';
+import { CustomFieldsForm } from '../CustomFieldsForm';
+import type { Contact, ContactType, ContactSource, EntityStatus, Company, CustomFieldValue } from '../types';
 import { CONTACT_SOURCE_LABELS, ENTITY_STATUS_LABELS } from '../types';

 interface ContactFormModalProps {
@ -47,9 +48,18 @@ export function ContactFormModal({
  const isEditMode = !!contact;
  const createMutation = useCreateContact();
  const updateMutation = useUpdateContact();
+  const setCustomFieldValues = useSetCustomFieldValues();
  const mutation = isEditMode ? updateMutation : createMutation;

  const [error, setError] = useState('');
+  const customFieldValuesRef = useRef<Record<string, string | number | boolean | string[] | null>>({});
+  const customFields: CustomFieldValue[] = contact?.customFields ?? [];
+  const handleCustomFieldsChange = useCallback(
+    (values: Record<string, string | number | boolean | string[] | null>) => {
+      customFieldValuesRef.current = values;
+    },
+    [],
+  );
  const [type, setType] = useState<ContactType>('PERSON');
  const [firstName, setFirstName] = useState('');
  const [lastName, setLastName] = useState('');
@ -211,11 +221,26 @@ export function ContactFormModal({
      ...(position ? { position } : {}),
    };

+    const saveCustomFields = (entityId: string) => {
+      const vals = customFieldValuesRef.current;
+      const entries = Object.entries(vals);
+      if (entries.length === 0) return;
+      setCustomFieldValues.mutate({
+        entityId,
+        data: {
+          values: entries.map(([fieldDefId, value]) => ({ fieldDefId, value })),
+        },
+      });
+    };
+
    if (isEditMode && contact) {
      updateMutation.mutate(
        { id: contact.id, data: payload },
        {
-          onSuccess: () => onSuccess(),
+          onSuccess: () => {
+            saveCustomFields(contact.id);
+            onSuccess();
+          },
          onError: (err: unknown) => {
            const msg =
              (err as { response?: { data?: { error?: { message?: string } } } })
@ -226,7 +251,10 @@ export function ContactFormModal({
      );
    } else {
      createMutation.mutate(payload, {
-        onSuccess: () => onSuccess(),
+        onSuccess: (res) => {
+          if (res?.data?.id) saveCustomFields(res.data.id);
+          onSuccess();
+        },
        onError: (err: unknown) => {
          const msg =
            (err as { response?: { data?: { error?: { message?: string } } } })
@ -569,6 +597,14 @@ export function ContactFormModal({
          />
        </div>

+        {/* Custom Fields */}
+        {customFields.length > 0 && (
+          <CustomFieldsForm
+            fields={customFields}
+            onChange={handleCustomFieldsChange}
+          />
+        )}
+
        {/* Tags */}
        <div style={{ marginBottom: '1.5rem' }}>
          <label style={labelStyle}>Tags (kommasepariert)</label>
--- a/packages/frontend/src/crm/deals/DealDetailPage.tsx
+++ b/packages/frontend/src/crm/deals/DealDetailPage.tsx
@ -4,6 +4,7 @@ import { useDeal, useDeleteDeal } from '../hooks';
 import { DealFormModal } from './DealFormModal';
 import { Modal } from '../../components/Modal';
 import { DealVouchersSection } from '../lexware/DealVouchersSection';
+import { CustomFieldsDisplay } from '../CustomFieldsDisplay';
 import type { DealStatus } from '../types';
 import { LOST_REASON_LABELS } from '../types';
 import styles from './DealDetailPage.module.css';
@ -261,6 +262,11 @@ export function DealDetailPage() {
        {deal.notes && (
          <p className={styles.notesText}>{deal.notes}</p>
        )}
+
+        {/* Custom Fields */}
+        {deal.customFields && deal.customFields.length > 0 && (
+          <CustomFieldsDisplay fields={deal.customFields} />
+        )}
      </div>

      {/* Belege (Lexware Vouchers) */}
--- a/packages/frontend/src/crm/deals/DealFormModal.tsx
+++ b/packages/frontend/src/crm/deals/DealFormModal.tsx
@ -1,8 +1,9 @@
-import { useState, useEffect, useRef } from 'react';
+import { useState, useEffect, useRef, useCallback } from 'react';
 import { Modal } from '../../components/Modal';
-import { useCreateDeal, useUpdateDeal, usePipelines } from '../hooks';
+import { useCreateDeal, useUpdateDeal, usePipelines, useSetCustomFieldValues } from '../hooks';
 import { contactsApi, companiesApi } from '../api';
-import type { Deal, DealStatus, LostReason, Contact, Company } from '../types';
+import { CustomFieldsForm } from '../CustomFieldsForm';
+import type { Deal, DealStatus, LostReason, Contact, Company, CustomFieldValue } from '../types';
 import { LOST_REASON_LABELS } from '../types';

 interface DealFormModalProps {
@ -53,8 +54,18 @@ export function DealFormModal({
  const isEditMode = !!deal;
  const createMutation = useCreateDeal();
  const updateMutation = useUpdateDeal();
+  const setCustomFieldValues = useSetCustomFieldValues();
  const mutation = isEditMode ? updateMutation : createMutation;

+  const customFieldValuesRef = useRef<Record<string, string | number | boolean | string[] | null>>({});
+  const customFields: CustomFieldValue[] = deal?.customFields ?? [];
+  const handleCustomFieldsChange = useCallback(
+    (values: Record<string, string | number | boolean | string[] | null>) => {
+      customFieldValuesRef.current = values;
+    },
+    [],
+  );
+
  const { data: pipelinesData } = usePipelines();
  const pipelines = pipelinesData?.data ?? [];

@ -269,11 +280,26 @@ export function DealFormModal({
      ...(status === 'LOST' && lostReasonText ? { lostReasonText } : {}),
    };

+    const saveCustomFields = (entityId: string) => {
+      const vals = customFieldValuesRef.current;
+      const entries = Object.entries(vals);
+      if (entries.length === 0) return;
+      setCustomFieldValues.mutate({
+        entityId,
+        data: {
+          values: entries.map(([fieldDefId, value]) => ({ fieldDefId, value })),
+        },
+      });
+    };
+
    if (isEditMode && deal) {
      updateMutation.mutate(
        { id: deal.id, data: payload },
        {
-          onSuccess: () => onSuccess(),
+          onSuccess: () => {
+            saveCustomFields(deal.id);
+            onSuccess();
+          },
          onError: (err: unknown) => {
            const msg =
              (err as { response?: { data?: { error?: { message?: string } } } })
@ -284,7 +310,10 @@ export function DealFormModal({
      );
    } else {
      createMutation.mutate(payload, {
-        onSuccess: () => onSuccess(),
+        onSuccess: (res) => {
+          if (res?.data?.id) saveCustomFields(res.data.id);
+          onSuccess();
+        },
        onError: (err: unknown) => {
          const msg =
            (err as { response?: { data?: { error?: { message?: string } } } })
@ -643,7 +672,7 @@ export function DealFormModal({
        )}

        {/* Notizen */}
-        <div style={{ marginBottom: '1.5rem' }}>
+        <div style={{ marginBottom: '1rem' }}>
          <label style={labelStyle}>Notizen</label>
          <textarea
            style={{ ...inputStyle, minHeight: 60, resize: 'vertical' }}
@ -652,6 +681,16 @@ export function DealFormModal({
          />
        </div>

+        {/* Custom Fields */}
+        {customFields.length > 0 && (
+          <div style={{ marginBottom: '1rem' }}>
+            <CustomFieldsForm
+              fields={customFields}
+              onChange={handleCustomFieldsChange}
+            />
+          </div>
+        )}
+
        {/* Buttons */}
        <div
          style={{
--- a/packages/frontend/src/crm/hooks.ts
+++ b/packages/frontend/src/crm/hooks.ts
@ -18,6 +18,7 @@ import {
  lexwareVouchersApi,
  tradeEventsApi,
  ownersApi,
+  customFieldsApi,
 } from './api';
 import type {
  ContactsQueryParams,
@ -48,6 +49,10 @@ import type {
  CreateTradeEventPayload,
  UpdateTradeEventPayload,
  AddOwnerPayload,
+  CustomFieldEntityType,
+  CreateCustomFieldDefPayload,
+  UpdateCustomFieldDefPayload,
+  SetCustomFieldValuesPayload,
 } from './types';

 // --- Query Key Factory ---
@ -111,6 +116,13 @@ export const crmKeys = {
    active: () => ['crm', 'tradeEvents', 'active'] as const,
    detail: (id: string) => ['crm', 'tradeEvents', 'detail', id] as const,
  },
+  customFields: {
+    all: ['crm', 'customFields'] as const,
+    defs: (entityType?: CustomFieldEntityType) =>
+      ['crm', 'customFields', 'defs', entityType] as const,
+    values: (entityId: string) =>
+      ['crm', 'customFields', 'values', entityId] as const,
+  },
  lexware: {
    all: ['crm', 'lexware'] as const,
    contactSearch: (params: LexwareContactSearchParams) =>
@ -1009,3 +1021,78 @@ export function useRemoveDealOwner() {
    },
  });
 }
+
+// ============================================================
+//  Custom Fields (Phase 2.1)
+// ============================================================
+
+export function useCustomFieldDefs(entityType?: CustomFieldEntityType) {
+  return useQuery({
+    queryKey: crmKeys.customFields.defs(entityType),
+    queryFn: () => customFieldsApi.listDefs(entityType),
+    staleTime: 5 * 60 * 1000,
+  });
+}
+
+export function useCreateCustomFieldDef() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: (data: CreateCustomFieldDefPayload) =>
+      customFieldsApi.createDef(data),
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: crmKeys.customFields.all });
+    },
+  });
+}
+
+export function useUpdateCustomFieldDef() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: ({ id, data }: { id: string; data: UpdateCustomFieldDefPayload }) =>
+      customFieldsApi.updateDef(id, data),
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: crmKeys.customFields.all });
+    },
+  });
+}
+
+export function useDeleteCustomFieldDef() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: (id: string) => customFieldsApi.deleteDef(id),
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: crmKeys.customFields.all });
+      // Invalidate entities too since their customFields arrays change
+      qc.invalidateQueries({ queryKey: crmKeys.contacts.all });
+      qc.invalidateQueries({ queryKey: crmKeys.companies.all });
+      qc.invalidateQueries({ queryKey: crmKeys.deals.all });
+    },
+  });
+}
+
+export function useCustomFieldValues(entityId: string) {
+  return useQuery({
+    queryKey: crmKeys.customFields.values(entityId),
+    queryFn: () => customFieldsApi.getValues(entityId),
+    enabled: !!entityId,
+  });
+}
+
+export function useSetCustomFieldValues() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: ({
+      entityId,
+      data,
+    }: {
+      entityId: string;
+      data: SetCustomFieldValuesPayload;
+    }) => customFieldsApi.setValues(entityId, data),
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: crmKeys.customFields.all });
+      qc.invalidateQueries({ queryKey: crmKeys.contacts.all });
+      qc.invalidateQueries({ queryKey: crmKeys.companies.all });
+      qc.invalidateQueries({ queryKey: crmKeys.deals.all });
+    },
+  });
+}
--- a/packages/frontend/src/crm/settings/CrmSettingsPage.tsx
+++ b/packages/frontend/src/crm/settings/CrmSettingsPage.tsx
@ -18,11 +18,23 @@ import {
  useCreateRelationshipType,
  useUpdateRelationshipType,
  useDeleteRelationshipType,
+  useCustomFieldDefs,
+  useCreateCustomFieldDef,
+  useUpdateCustomFieldDef,
+  useDeleteCustomFieldDef,
 } from '../hooks';
 import type {
  Industry,
  AccountType,
  RelationshipType,
+  CustomFieldDef,
+  CustomFieldEntityType,
+  CustomFieldType,
+  CustomFieldOption,
+} from '../types';
+import {
+  CUSTOM_FIELD_ENTITY_TYPE_LABELS,
+  CUSTOM_FIELD_TYPE_LABELS,
 } from '../types';
 import { LexwareSyncContent } from '../lexware/LexwareSyncPage';
 import styles from './CrmSettingsPage.module.css';
@ -673,11 +685,502 @@ function RelationshipTypesConfig() {
  );
 }

+// ============================================================
+//  CustomFieldsConfig (Phase 2.1)
+// ============================================================
+
+const ENTITY_TYPES: CustomFieldEntityType[] = ['PERSON', 'COMPANY', 'DEAL'];
+const FIELD_TYPES: CustomFieldType[] = [
+  'TEXT', 'TEXTAREA', 'NUMBER', 'DATE', 'DROPDOWN', 'MULTI_SELECT', 'CHECKBOX', 'URL',
+];
+
+const needsOptions = (ft: CustomFieldType) => ft === 'DROPDOWN' || ft === 'MULTI_SELECT';
+
+function CustomFieldsConfig() {
+  const [entityFilter, setEntityFilter] = useState<CustomFieldEntityType>('PERSON');
+  const { data, isLoading } = useCustomFieldDefs(entityFilter);
+  const createMut = useCreateCustomFieldDef();
+  const updateMut = useUpdateCustomFieldDef();
+  const deleteMut = useDeleteCustomFieldDef();
+
+  const defs: CustomFieldDef[] = data?.data ?? [];
+
+  // Add mode state
+  const [addMode, setAddMode] = useState(false);
+  const [newLabel, setNewLabel] = useState('');
+  const [newFieldType, setNewFieldType] = useState<CustomFieldType>('TEXT');
+  const [newRequired, setNewRequired] = useState(false);
+  const [newOptions, setNewOptions] = useState<CustomFieldOption[]>([]);
+  const [newOptionValue, setNewOptionValue] = useState('');
+  const [newOptionLabel, setNewOptionLabel] = useState('');
+
+  // Edit mode state
+  const [editId, setEditId] = useState<string | null>(null);
+  const [editLabel, setEditLabel] = useState('');
+  const [editRequired, setEditRequired] = useState(false);
+  const [editOptions, setEditOptions] = useState<CustomFieldOption[]>([]);
+  const [editOptionValue, setEditOptionValue] = useState('');
+  const [editOptionLabel, setEditOptionLabel] = useState('');
+
+  const resetAdd = useCallback(() => {
+    setAddMode(false);
+    setNewLabel('');
+    setNewFieldType('TEXT');
+    setNewRequired(false);
+    setNewOptions([]);
+    setNewOptionValue('');
+    setNewOptionLabel('');
+  }, []);
+
+  const resetEdit = useCallback(() => {
+    setEditId(null);
+    setEditLabel('');
+    setEditRequired(false);
+    setEditOptions([]);
+    setEditOptionValue('');
+    setEditOptionLabel('');
+  }, []);
+
+  const startEdit = useCallback((def: CustomFieldDef) => {
+    setAddMode(false);
+    setEditId(def.id);
+    setEditLabel(def.label);
+    setEditRequired(def.isRequired);
+    setEditOptions(def.options ?? []);
+  }, []);
+
+  const handleCreate = useCallback(() => {
+    if (!newLabel.trim()) return;
+    const payload: {
+      entityType: CustomFieldEntityType;
+      label: string;
+      fieldType: CustomFieldType;
+      isRequired: boolean;
+      options?: CustomFieldOption[];
+    } = {
+      entityType: entityFilter,
+      label: newLabel.trim(),
+      fieldType: newFieldType,
+      isRequired: newRequired,
+    };
+    if (needsOptions(newFieldType) && newOptions.length > 0) {
+      payload.options = newOptions;
+    }
+    createMut.mutate(payload, { onSuccess: resetAdd });
+  }, [entityFilter, newLabel, newFieldType, newRequired, newOptions, createMut, resetAdd]);
+
+  const handleUpdate = useCallback(() => {
+    if (!editId || !editLabel.trim()) return;
+    const def = defs.find((d) => d.id === editId);
+    if (!def) return;
+    const payload: { label: string; isRequired: boolean; options?: CustomFieldOption[] } = {
+      label: editLabel.trim(),
+      isRequired: editRequired,
+    };
+    if (needsOptions(def.fieldType)) {
+      payload.options = editOptions;
+    }
+    updateMut.mutate({ id: editId, data: payload }, { onSuccess: resetEdit });
+  }, [editId, editLabel, editRequired, editOptions, defs, updateMut, resetEdit]);
+
+  const handleDelete = useCallback(
+    (id: string) => {
+      if (window.confirm('Benutzerdefiniertes Feld wirklich loeschen? Alle gespeicherten Werte werden ebenfalls geloescht!')) {
+        deleteMut.mutate(id);
+      }
+    },
+    [deleteMut],
+  );
+
+  const handleSort = useCallback(
+    (def: CustomFieldDef, direction: 'up' | 'down') => {
+      const newPos = direction === 'up' ? Math.max(0, def.position - 1) : def.position + 1;
+      updateMut.mutate({ id: def.id, data: { position: newPos } });
+    },
+    [updateMut],
+  );
+
+  const addNewOption = useCallback(() => {
+    if (!newOptionValue.trim() || !newOptionLabel.trim()) return;
+    setNewOptions((prev) => [...prev, { value: newOptionValue.trim(), label: newOptionLabel.trim() }]);
+    setNewOptionValue('');
+    setNewOptionLabel('');
+  }, [newOptionValue, newOptionLabel]);
+
+  const addEditOption = useCallback(() => {
+    if (!editOptionValue.trim() || !editOptionLabel.trim()) return;
+    setEditOptions((prev) => [...prev, { value: editOptionValue.trim(), label: editOptionLabel.trim() }]);
+    setEditOptionValue('');
+    setEditOptionLabel('');
+  }, [editOptionValue, editOptionLabel]);
+
+  const isSaving = createMut.isPending || updateMut.isPending;
+
+  const optionBadgeStyle: React.CSSProperties = {
+    display: 'inline-flex',
+    alignItems: 'center',
+    gap: '0.25rem',
+    padding: '0.125rem 0.5rem',
+    background: 'var(--color-bg)',
+    border: '1px solid var(--color-border)',
+    borderRadius: '9999px',
+    fontSize: '0.75rem',
+    color: 'var(--color-text-secondary)',
+  };
+
+  const optionRemoveStyle: React.CSSProperties = {
+    background: 'none',
+    border: 'none',
+    cursor: 'pointer',
+    fontSize: '0.875rem',
+    lineHeight: 1,
+    color: 'var(--color-text-muted)',
+    padding: 0,
+  };
+
+  return (
+    <div className={styles.card}>
+      <div className={styles.configHeader}>
+        <div>
+          <h2 className={styles.cardTitle}>Benutzerdefinierte Felder</h2>
+          <p className={styles.cardDesc} style={{ marginBottom: 0 }}>
+            Individuelle Datenfelder fuer Kontakte, Unternehmen und Vorgaenge.
+          </p>
+        </div>
+        <button className={styles.addBtn} onClick={() => { resetEdit(); setAddMode(true); }} disabled={addMode}>
+          <PlusIcon /> Neues Feld
+        </button>
+      </div>
+
+      {/* Entity-Typ Filter */}
+      <div style={{ display: 'flex', gap: '0.25rem', marginBottom: '1rem' }}>
+        {ENTITY_TYPES.map((et) => (
+          <button
+            key={et}
+            onClick={() => { setEntityFilter(et); resetAdd(); resetEdit(); }}
+            style={{
+              padding: '0.375rem 0.75rem',
+              fontSize: '0.8125rem',
+              fontWeight: 500,
+              border: '1px solid',
+              borderColor: entityFilter === et ? 'var(--color-primary)' : 'var(--color-border)',
+              borderRadius: 'var(--radius-sm)',
+              background: entityFilter === et ? 'var(--color-primary)' : 'transparent',
+              color: entityFilter === et ? 'white' : 'var(--color-text-secondary)',
+              cursor: 'pointer',
+              transition: 'all 0.15s',
+            }}
+          >
+            {CUSTOM_FIELD_ENTITY_TYPE_LABELS[et]}
+          </button>
+        ))}
+      </div>
+
+      {/* Add form */}
+      {addMode && (
+        <div style={{
+          padding: '1rem',
+          marginBottom: '1rem',
+          background: 'var(--color-bg)',
+          borderRadius: 'var(--radius-sm)',
+          border: '1px solid var(--color-border)',
+        }}>
+          <div style={{ display: 'grid', gridTemplateColumns: '1fr 1fr', gap: '0.75rem', marginBottom: '0.75rem' }}>
+            <div>
+              <label style={{ fontSize: '0.8125rem', fontWeight: 500, display: 'block', marginBottom: '0.25rem' }}>
+                Bezeichnung *
+              </label>
+              <input
+                className={styles.inlineInput}
+                style={{ width: '100%' }}
+                value={newLabel}
+                onChange={(e) => setNewLabel(e.target.value)}
+                placeholder="z.B. Kundennummer"
+                autoFocus
+              />
+            </div>
+            <div>
+              <label style={{ fontSize: '0.8125rem', fontWeight: 500, display: 'block', marginBottom: '0.25rem' }}>
+                Feldtyp *
+              </label>
+              <select
+                className={styles.inlineInput}
+                style={{ width: '100%', cursor: 'pointer' }}
+                value={newFieldType}
+                onChange={(e) => setNewFieldType(e.target.value as CustomFieldType)}
+              >
+                {FIELD_TYPES.map((ft) => (
+                  <option key={ft} value={ft}>{CUSTOM_FIELD_TYPE_LABELS[ft]}</option>
+                ))}
+              </select>
+            </div>
+          </div>
+
+          <div style={{ display: 'flex', alignItems: 'center', gap: '0.5rem', marginBottom: '0.75rem' }}>
+            <label style={{ display: 'flex', alignItems: 'center', gap: '0.375rem', fontSize: '0.8125rem', cursor: 'pointer' }}>
+              <input
+                type="checkbox"
+                checked={newRequired}
+                onChange={(e) => setNewRequired(e.target.checked)}
+              />
+              Pflichtfeld
+            </label>
+          </div>
+
+          {/* Options editor for DROPDOWN / MULTI_SELECT */}
+          {needsOptions(newFieldType) && (
+            <div style={{ marginBottom: '0.75rem' }}>
+              <label style={{ fontSize: '0.8125rem', fontWeight: 500, display: 'block', marginBottom: '0.375rem' }}>
+                Optionen
+              </label>
+              <div style={{ display: 'flex', flexWrap: 'wrap', gap: '0.25rem', marginBottom: '0.5rem' }}>
+                {newOptions.map((opt, i) => (
+                  <span key={i} style={optionBadgeStyle}>
+                    {opt.label}
+                    <button style={optionRemoveStyle} onClick={() => setNewOptions((prev) => prev.filter((_, j) => j !== i))}>
+                      &times;
+                    </button>
+                  </span>
+                ))}
+                {newOptions.length === 0 && (
+                  <span style={{ fontSize: '0.8125rem', color: 'var(--color-text-muted)', fontStyle: 'italic' }}>
+                    Noch keine Optionen
+                  </span>
+                )}
+              </div>
+              <div style={{ display: 'flex', gap: '0.5rem', alignItems: 'center' }}>
+                <input
+                  className={styles.inlineInput}
+                  value={newOptionValue}
+                  onChange={(e) => setNewOptionValue(e.target.value)}
+                  placeholder="Wert"
+                  style={{ width: 120 }}
+                  onKeyDown={(e) => { if (e.key === 'Enter') addNewOption(); }}
+                />
+                <input
+                  className={styles.inlineInput}
+                  value={newOptionLabel}
+                  onChange={(e) => setNewOptionLabel(e.target.value)}
+                  placeholder="Anzeige-Name"
+                  style={{ flex: 1 }}
+                  onKeyDown={(e) => { if (e.key === 'Enter') addNewOption(); }}
+                />
+                <button
+                  className={styles.saveBtn}
+                  onClick={addNewOption}
+                  disabled={!newOptionValue.trim() || !newOptionLabel.trim()}
+                  style={{ padding: '0.375rem 0.625rem', fontSize: '0.75rem' }}
+                >
+                  +
+                </button>
+              </div>
+            </div>
+          )}
+
+          <div style={{ display: 'flex', gap: '0.5rem', justifyContent: 'flex-end' }}>
+            <button className={styles.cancelBtn} onClick={resetAdd}>Abbrechen</button>
+            <button
+              className={styles.saveBtn}
+              onClick={handleCreate}
+              disabled={!newLabel.trim() || isSaving || (needsOptions(newFieldType) && newOptions.length === 0)}
+            >
+              {createMut.isPending ? 'Erstellen...' : 'Feld erstellen'}
+            </button>
+          </div>
+        </div>
+      )}
+
+      {/* Table */}
+      {isLoading ? (
+        <p style={{ fontSize: '0.875rem', color: 'var(--color-text-muted)' }}>Laden...</p>
+      ) : (
+        <table className={styles.configTable}>
+          <thead>
+            <tr>
+              <th style={{ width: 40 }}>#</th>
+              <th>Bezeichnung</th>
+              <th>Typ</th>
+              <th style={{ width: 60 }}>Pflicht</th>
+              <th style={{ width: 120, textAlign: 'right' }}>Aktionen</th>
+            </tr>
+          </thead>
+          <tbody>
+            {defs.length === 0 && !addMode && (
+              <tr>
+                <td colSpan={5} className={styles.emptyRow}>
+                  Noch keine Felder fuer {CUSTOM_FIELD_ENTITY_TYPE_LABELS[entityFilter]} definiert
+                </td>
+              </tr>
+            )}
+            {defs.map((def, idx) =>
+              editId === def.id ? (
+                <tr key={def.id}>
+                  <td>{idx + 1}</td>
+                  <td colSpan={4}>
+                    <div style={{
+                      padding: '0.75rem',
+                      background: 'var(--color-bg)',
+                      borderRadius: 'var(--radius-sm)',
+                      border: '1px solid var(--color-border)',
+                    }}>
+                      <div style={{ display: 'grid', gridTemplateColumns: '1fr auto', gap: '0.75rem', marginBottom: '0.5rem', alignItems: 'end' }}>
+                        <div>
+                          <label style={{ fontSize: '0.75rem', fontWeight: 500, display: 'block', marginBottom: '0.25rem' }}>
+                            Bezeichnung
+                          </label>
+                          <input
+                            className={styles.inlineInput}
+                            style={{ width: '100%' }}
+                            value={editLabel}
+                            onChange={(e) => setEditLabel(e.target.value)}
+                            autoFocus
+                          />
+                        </div>
+                        <div style={{ display: 'flex', alignItems: 'center', gap: '0.375rem', paddingBottom: '0.25rem' }}>
+                          <label style={{ display: 'flex', alignItems: 'center', gap: '0.25rem', fontSize: '0.8125rem', cursor: 'pointer' }}>
+                            <input type="checkbox" checked={editRequired} onChange={(e) => setEditRequired(e.target.checked)} />
+                            Pflicht
+                          </label>
+                        </div>
+                      </div>
+                      <div style={{ fontSize: '0.75rem', color: 'var(--color-text-muted)', marginBottom: '0.5rem' }}>
+                        Typ: {CUSTOM_FIELD_TYPE_LABELS[def.fieldType]} (nicht aenderbar) &middot; Slug: {def.name}
+                      </div>
+
+                      {needsOptions(def.fieldType) && (
+                        <div style={{ marginBottom: '0.75rem' }}>
+                          <label style={{ fontSize: '0.75rem', fontWeight: 500, display: 'block', marginBottom: '0.375rem' }}>
+                            Optionen
+                          </label>
+                          <div style={{ display: 'flex', flexWrap: 'wrap', gap: '0.25rem', marginBottom: '0.5rem' }}>
+                            {editOptions.map((opt, i) => (
+                              <span key={i} style={optionBadgeStyle}>
+                                {opt.label} ({opt.value})
+                                <button style={optionRemoveStyle} onClick={() => setEditOptions((prev) => prev.filter((_, j) => j !== i))}>
+                                  &times;
+                                </button>
+                              </span>
+                            ))}
+                          </div>
+                          <div style={{ display: 'flex', gap: '0.5rem', alignItems: 'center' }}>
+                            <input
+                              className={styles.inlineInput}
+                              value={editOptionValue}
+                              onChange={(e) => setEditOptionValue(e.target.value)}
+                              placeholder="Wert"
+                              style={{ width: 120 }}
+                              onKeyDown={(e) => { if (e.key === 'Enter') addEditOption(); }}
+                            />
+                            <input
+                              className={styles.inlineInput}
+                              value={editOptionLabel}
+                              onChange={(e) => setEditOptionLabel(e.target.value)}
+                              placeholder="Anzeige-Name"
+                              style={{ flex: 1 }}
+                              onKeyDown={(e) => { if (e.key === 'Enter') addEditOption(); }}
+                            />
+                            <button
+                              className={styles.saveBtn}
+                              onClick={addEditOption}
+                              disabled={!editOptionValue.trim() || !editOptionLabel.trim()}
+                              style={{ padding: '0.375rem 0.625rem', fontSize: '0.75rem' }}
+                            >
+                              +
+                            </button>
+                          </div>
+                        </div>
+                      )}
+
+                      <div style={{ display: 'flex', gap: '0.5rem', justifyContent: 'flex-end' }}>
+                        <button className={styles.cancelBtn} onClick={resetEdit}>Abbrechen</button>
+                        <button
+                          className={styles.saveBtn}
+                          onClick={handleUpdate}
+                          disabled={!editLabel.trim() || isSaving}
+                        >
+                          {updateMut.isPending ? 'Speichern...' : 'Speichern'}
+                        </button>
+                      </div>
+                    </div>
+                  </td>
+                </tr>
+              ) : (
+                <tr key={def.id}>
+                  <td>
+                    <div className={styles.sortBtns}>
+                      <button className={styles.sortBtn} onClick={() => handleSort(def, 'up')} disabled={idx === 0} title="Nach oben">
+                        <ArrowUpIcon />
+                      </button>
+                      <button className={styles.sortBtn} onClick={() => handleSort(def, 'down')} disabled={idx === defs.length - 1} title="Nach unten">
+                        <ArrowDownIcon />
+                      </button>
+                    </div>
+                  </td>
+                  <td>
+                    <div>
+                      <span style={{ fontWeight: 500 }}>{def.label}</span>
+                      <span style={{ color: 'var(--color-text-muted)', fontSize: '0.75rem', marginLeft: '0.5rem' }}>
+                        ({def.name})
+                      </span>
+                    </div>
+                    {def.options && def.options.length > 0 && (
+                      <div style={{ display: 'flex', flexWrap: 'wrap', gap: '0.25rem', marginTop: '0.25rem' }}>
+                        {def.options.map((opt, i) => (
+                          <span key={i} style={{ ...optionBadgeStyle, fontSize: '0.6875rem' }}>
+                            {opt.label}
+                          </span>
+                        ))}
+                      </div>
+                    )}
+                  </td>
+                  <td>
+                    <span style={{
+                      display: 'inline-block',
+                      padding: '0.125rem 0.375rem',
+                      background: '#f3f4f6',
+                      borderRadius: '4px',
+                      fontSize: '0.75rem',
+                      color: '#4b5563',
+                    }}>
+                      {CUSTOM_FIELD_TYPE_LABELS[def.fieldType]}
+                    </span>
+                  </td>
+                  <td style={{ textAlign: 'center' }}>
+                    {def.isRequired ? (
+                      <span style={{ color: 'var(--color-primary)', fontWeight: 600, fontSize: '0.875rem' }}>Ja</span>
+                    ) : (
+                      <span style={{ color: 'var(--color-text-muted)', fontSize: '0.8125rem' }}>&mdash;</span>
+                    )}
+                  </td>
+                  <td>
+                    <div className={styles.actionsCell}>
+                      <button className={styles.iconBtn} onClick={() => startEdit(def)} title="Bearbeiten">
+                        <PencilIcon />
+                      </button>
+                      <button
+                        className={`${styles.iconBtn} ${styles.iconBtnDanger}`}
+                        onClick={() => handleDelete(def.id)}
+                        title="Loeschen"
+                      >
+                        <TrashIcon />
+                      </button>
+                    </div>
+                  </td>
+                </tr>
+              ),
+            )}
+          </tbody>
+        </table>
+      )}
+    </div>
+  );
+}
+
 // ============================================================
 //  Page Component
 // ============================================================

-type SettingsTab = 'module' | 'lexware' | 'settings';
+type SettingsTab = 'module' | 'customfields' | 'lexware' | 'settings';

 export function CrmSettingsPage() {
  const { user } = useAuth();
@ -741,6 +1244,25 @@ export function CrmSettingsPage() {
          </svg>
          Module
        </button>
+        <button
+          className={`${styles.settingsTab} ${activeTab === 'customfields' ? styles.settingsTabActive : ''}`}
+          onClick={() => setActiveTab('customfields')}
+        >
+          <svg
+            width="16"
+            height="16"
+            viewBox="0 0 16 16"
+            fill="none"
+            stroke="currentColor"
+            strokeWidth="1.5"
+            strokeLinecap="round"
+            strokeLinejoin="round"
+          >
+            <path d="M3 3h10v10H3z" />
+            <path d="M6 6h4M6 8.5h4M6 11h2" />
+          </svg>
+          Eigene Felder
+        </button>
        <button
          className={`${styles.settingsTab} ${activeTab === 'lexware' ? styles.settingsTabActive : ''}`}
          onClick={() => setActiveTab('lexware')}
@ -879,6 +1401,11 @@ export function CrmSettingsPage() {
        </div>
      )}

+      {/* Tab: Custom Fields */}
+      {activeTab === 'customfields' && (
+        <CustomFieldsConfig />
+      )}
+
      {/* Tab: Lexoffice Sync */}
      {activeTab === 'lexware' && (
        <>
--- a/packages/frontend/src/crm/types.ts
+++ b/packages/frontend/src/crm/types.ts
@ -259,6 +259,7 @@ export interface Contact {
  phones?: ContactPhone[];
  owners?: EntityOwner[];
  activities?: Activity[];
+  customFields?: CustomFieldValue[];
  company?: {
    id: string;
    name: string;
@ -410,6 +411,7 @@ export interface Deal {
  createdAt: string;
  updatedAt: string;
  owners?: EntityOwner[];
+  customFields?: CustomFieldValue[];
  pipeline?: { id: string; name: string; stages?: PipelineStage[] };
  stage?: { id: string; name: string; color: string };
  contact?: {
@ -483,6 +485,7 @@ export interface Company {
  emails?: ContactEmail[];
  phones?: ContactPhone[];
  owners?: EntityOwner[];
+  customFields?: CustomFieldValue[];
  industryRef?: Industry | null;
  accountType?: AccountType | null;
  _count?: { contacts: number; deals: number; lexwareVouchers?: number; contracts?: number };
@ -734,3 +737,85 @@ export interface UpdateTradeEventPayload {
  isActive?: boolean;
  sortOrder?: number;
 }
+
+// ============================================================
+//  Custom Fields (Phase 2.1)
+// ============================================================
+
+export type CustomFieldEntityType = 'PERSON' | 'COMPANY' | 'DEAL';
+export type CustomFieldType =
+  | 'TEXT'
+  | 'TEXTAREA'
+  | 'NUMBER'
+  | 'DATE'
+  | 'DROPDOWN'
+  | 'MULTI_SELECT'
+  | 'CHECKBOX'
+  | 'URL';
+
+export const CUSTOM_FIELD_ENTITY_TYPE_LABELS: Record<CustomFieldEntityType, string> = {
+  PERSON: 'Kontakte',
+  COMPANY: 'Unternehmen',
+  DEAL: 'Vorgaenge',
+};
+
+export const CUSTOM_FIELD_TYPE_LABELS: Record<CustomFieldType, string> = {
+  TEXT: 'Text',
+  TEXTAREA: 'Textbereich',
+  NUMBER: 'Zahl',
+  DATE: 'Datum',
+  DROPDOWN: 'Dropdown',
+  MULTI_SELECT: 'Mehrfachauswahl',
+  CHECKBOX: 'Checkbox',
+  URL: 'URL',
+};
+
+export interface CustomFieldOption {
+  value: string;
+  label: string;
+}
+
+export interface CustomFieldDef {
+  id: string;
+  tenantId: string;
+  entityType: CustomFieldEntityType;
+  name: string;
+  label: string;
+  fieldType: CustomFieldType;
+  options: CustomFieldOption[] | null;
+  isRequired: boolean;
+  position: number;
+  createdAt: string;
+  updatedAt: string;
+}
+
+export interface CustomFieldValue {
+  fieldDefId: string;
+  name: string;
+  label: string;
+  fieldType: CustomFieldType;
+  value: string | number | boolean | string[] | null;
+}
+
+export interface CreateCustomFieldDefPayload {
+  entityType: CustomFieldEntityType;
+  label: string;
+  fieldType: CustomFieldType;
+  options?: CustomFieldOption[];
+  isRequired?: boolean;
+  position?: number;
+}
+
+export interface UpdateCustomFieldDefPayload {
+  label?: string;
+  options?: CustomFieldOption[];
+  isRequired?: boolean;
+  position?: number;
+}
+
+export interface SetCustomFieldValuesPayload {
+  values: Array<{
+    fieldDefId: string;
+    value: string | number | boolean | string[] | null;
+  }>;
+}
--- a/packages/frontend/vite.config.ts
+++ b/packages/frontend/vite.config.ts
@ -12,6 +12,7 @@ export default defineConfig({
  server: {
    port: 8080,
    host: true,
+    allowedHosts: ['.xinion.lan'],
    proxy: {
      '/api/v1/crm': {
        target: 'http://localhost:3100',