feat(customers): add dashboard and customer management

2026-07-02 23:37:46 +02:00 · 2026-07-02 23:37:46 +02:00 · 92cb8d1286
commit 92cb8d1286
parent 694b7bd09a
28 changed files with 2521 additions and 13 deletions
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@ -158,6 +158,20 @@ Hermes

 Athena ist die einzige API-Oberflaeche fuer den Browser.

+## Dashboard
+
+Das Dashboard liegt in Athena unter `/dashboard` und bezieht seine Daten ueber die BFF-Route `GET /api/dashboard/summary`.
+
+Hermes stellt dafuer `GET /dashboard/summary` bereit. Der Endpunkt ist mit `dashboard.read` geschuetzt und liefert nur Datenbloecke, fuer die der aktuelle Benutzer weitere Berechtigungen besitzt.
+
+Beispiele:
+
+- Kundenstatistiken nur mit `customers.read`
+- Benutzerstatistiken nur mit `users.read`
+- Rollenstatus nur mit `roles.read`
+
+Nicht vorhandene Module wie Aufgaben, Tickets oder Projekte werden nicht mit Fake-Daten gefuellt. Stattdessen liefert das Dashboard leere Widgets mit klarer Meldung.
+
 ## RBAC: Rollen und Berechtigungen

 Olympus verwendet ein serverseitiges RBAC-System als Grundlage fuer alle CRM-Module.
@ -309,6 +323,57 @@ Der aktuell angemeldete Benutzer darf sich nicht selbst loeschen. Hermes verhind

 Benutzer besitzen eine primaere RBAC-Rolle ueber `role_id`. Die Rolle bestimmt die serverseitigen Berechtigungen.

+## Kundenmodul
+
+Das Kundenmodul ist das zweite Enterprise-Modul und folgt den gleichen Grundsaetzen wie die Benutzerverwaltung:
+
+- Hermes stellt REST-Endpunkte bereit.
+- Athena proxyt diese Endpunkte ueber `/api/customers`.
+- Der Browser spricht nicht direkt mit Hermes.
+- Berechtigungen werden serverseitig in Hermes geprueft.
+- Die UI nutzt Permissions nur fuer Sichtbarkeit und Bedienkomfort.
+
+Hermes-Endpunkte:
+
+- `GET /customers`
+- `GET /customers/{id}`
+- `POST /customers`
+- `PUT /customers/{id}`
+- `DELETE /customers/{id}`
+- `GET /customers/{id}/contacts`
+- `POST /customers/{id}/contacts`
+- `PUT /customers/{id}/contacts/{contact_id}`
+- `DELETE /customers/{id}/contacts/{contact_id}`
+
+Athena-BFF-Routen:
+
+- `GET /api/customers`
+- `POST /api/customers`
+- `GET /api/customers/[id]`
+- `PUT /api/customers/[id]`
+- `DELETE /api/customers/[id]`
+- `GET /api/customers/[id]/contacts`
+- `POST /api/customers/[id]/contacts`
+- `PUT /api/customers/[id]/contacts/[contactId]`
+- `DELETE /api/customers/[id]/contacts/[contactId]`
+
+Tabellen:
+
+- `customers`
+- `customer_addresses`
+- `customer_contacts`
+
+Kunden-Permissions:
+
+- `customers.read`
+- `customers.create`
+- `customers.update`
+- `customers.delete`
+
+Kontakte und Adressen gehoeren fachlich zum Kunden und werden aktuell ueber `customers.read` beziehungsweise `customers.update` gesteuert.
+
+Ein Kunden-Delete entfernt aktuell den Kunden inklusive Adressen und Ansprechpartnern. Fuer spaetere Projekte oder Tickets ist ein fachlicher Loeschschutz vorzubereiten, sobald diese Module existieren.
+
 ## Verzeichnisstruktur

 ```text
@ -328,6 +393,7 @@ backend/hermes
 frontend/athena
  app/
    api/
+    customers/
    roles/
    users/
  components/
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@ -164,6 +164,23 @@ Neue Module sollen mindestens diese UI-Zustaende unterstuetzen:
 - Validierung
 - Erfolg ohne Page Reload

+### CRM-Modulstandard
+
+Ein neues CRM-Modul soll sich am Kundenmodul orientieren:
+
+- SQLAlchemy-Modell in `backend/hermes/app/models`
+- Pydantic-Schemas in `backend/hermes/app/schemas`
+- Repository in `backend/hermes/app/repositories`
+- FastAPI-Router in `backend/hermes/app/api`
+- Alembic-Migration fuer Schemaaenderungen
+- Athena-BFF-Routen unter `frontend/athena/app/api`
+- Frontend-Seiten unter `frontend/athena/app/<module>`
+- wiederverwendbare UI-Komponenten unter `frontend/athena/components`
+- RBAC-Permissions vor der UI-Integration definieren
+- keine Fake-Daten fuer noch nicht existierende Unterbereiche
+
+Dashboard-Widgets fuer noch nicht implementierte Module muessen Empty States anzeigen statt hart codierter Beispieldaten.
+
 ### Neue Permissions

 Neue Module muessen eigene stabile Permission-Strings erhalten.
--- a/backend/hermes/alembic/versions/9c1d8a2f6b44_create_customers.py
+++ b/backend/hermes/alembic/versions/9c1d8a2f6b44_create_customers.py
@ -0,0 +1,94 @@
+"""create customers
+
+Revision ID: 9c1d8a2f6b44
+Revises: 7b2c9f4a0d31
+Create Date: 2026-07-02 14:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision: str = "9c1d8a2f6b44"
+down_revision: Union[str, Sequence[str], None] = "7b2c9f4a0d31"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "customers",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("customer_number", sa.String(length=50), nullable=False),
+        sa.Column("company_name", sa.String(length=255), nullable=False),
+        sa.Column("legal_name", sa.String(length=255), server_default="", nullable=False),
+        sa.Column("customer_type", sa.String(length=50), nullable=False),
+        sa.Column("status", sa.String(length=50), nullable=False),
+        sa.Column("industry", sa.String(length=120), server_default="", nullable=False),
+        sa.Column("website", sa.String(length=255), server_default="", nullable=False),
+        sa.Column("email", sa.String(length=255), server_default="", nullable=False),
+        sa.Column("phone", sa.String(length=80), server_default="", nullable=False),
+        sa.Column("tax_number", sa.String(length=120), server_default="", nullable=False),
+        sa.Column("vat_id", sa.String(length=120), server_default="", nullable=False),
+        sa.Column("notes", sa.Text(), server_default="", nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_customers_company_name"), "customers", ["company_name"], unique=False)
+    op.create_index(op.f("ix_customers_customer_number"), "customers", ["customer_number"], unique=True)
+    op.create_index(op.f("ix_customers_customer_type"), "customers", ["customer_type"], unique=False)
+    op.create_index(op.f("ix_customers_status"), "customers", ["status"], unique=False)
+
+    op.create_table(
+        "customer_addresses",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("customer_id", sa.Integer(), nullable=False),
+        sa.Column("type", sa.String(length=50), nullable=False),
+        sa.Column("street", sa.String(length=255), server_default="", nullable=False),
+        sa.Column("postal_code", sa.String(length=30), server_default="", nullable=False),
+        sa.Column("city", sa.String(length=120), server_default="", nullable=False),
+        sa.Column("state", sa.String(length=120), server_default="", nullable=False),
+        sa.Column("country", sa.String(length=120), server_default="Deutschland", nullable=False),
+        sa.Column("is_primary", sa.Boolean(), server_default=sa.false(), nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.ForeignKeyConstraint(["customer_id"], ["customers.id"], ondelete="CASCADE"),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_customer_addresses_customer_id"), "customer_addresses", ["customer_id"], unique=False)
+    op.create_index(op.f("ix_customer_addresses_type"), "customer_addresses", ["type"], unique=False)
+
+    op.create_table(
+        "customer_contacts",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("customer_id", sa.Integer(), nullable=False),
+        sa.Column("first_name", sa.String(length=100), server_default="", nullable=False),
+        sa.Column("last_name", sa.String(length=100), server_default="", nullable=False),
+        sa.Column("position", sa.String(length=120), server_default="", nullable=False),
+        sa.Column("email", sa.String(length=255), server_default="", nullable=False),
+        sa.Column("phone", sa.String(length=80), server_default="", nullable=False),
+        sa.Column("mobile", sa.String(length=80), server_default="", nullable=False),
+        sa.Column("is_primary", sa.Boolean(), server_default=sa.false(), nullable=False),
+        sa.Column("notes", sa.Text(), server_default="", nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.ForeignKeyConstraint(["customer_id"], ["customers.id"], ondelete="CASCADE"),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_customer_contacts_customer_id"), "customer_contacts", ["customer_id"], unique=False)
+
+
+def downgrade() -> None:
+    op.drop_index(op.f("ix_customer_contacts_customer_id"), table_name="customer_contacts")
+    op.drop_table("customer_contacts")
+    op.drop_index(op.f("ix_customer_addresses_type"), table_name="customer_addresses")
+    op.drop_index(op.f("ix_customer_addresses_customer_id"), table_name="customer_addresses")
+    op.drop_table("customer_addresses")
+    op.drop_index(op.f("ix_customers_status"), table_name="customers")
+    op.drop_index(op.f("ix_customers_customer_type"), table_name="customers")
+    op.drop_index(op.f("ix_customers_customer_number"), table_name="customers")
+    op.drop_index(op.f("ix_customers_company_name"), table_name="customers")
+    op.drop_table("customers")
--- a/backend/hermes/app/api/customers.py
+++ b/backend/hermes/app/api/customers.py
@ -0,0 +1,208 @@
+import logging
+
+from fastapi import APIRouter, Depends, HTTPException, Response, status
+from sqlalchemy.orm import Session
+
+from app.core.rbac import require_permission
+from app.db.database import get_db
+from app.models.customer import Customer, CustomerContact
+from app.models.user import User
+from app.repositories.customer_repository import CustomerRepository
+from app.schemas.customer import (
+    CustomerContactCreate,
+    CustomerContactResponse,
+    CustomerContactUpdate,
+    CustomerCreate,
+    CustomerResponse,
+    CustomerUpdate,
+)
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter(
+    prefix="/customers",
+    tags=["Customers"],
+)
+
+
+def get_customer_or_404(db: Session, customer_id: int) -> Customer:
+    customer = CustomerRepository.get_by_id(db, customer_id)
+    if customer is None:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Kunde nicht gefunden",
+        )
+    return customer
+
+
+def get_contact_or_404(db: Session, customer_id: int, contact_id: int) -> CustomerContact:
+    contact = CustomerRepository.get_contact_by_id(db, customer_id, contact_id)
+    if contact is None:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Ansprechpartner nicht gefunden",
+        )
+    return contact
+
+
+def ensure_unique_customer_number(
+    db: Session,
+    customer_number: str,
+    customer_id: int | None = None,
+) -> None:
+    conflict = CustomerRepository.find_number_conflict(
+        db,
+        customer_number=customer_number,
+        exclude_customer_id=customer_id,
+    )
+    if conflict is not None:
+        raise HTTPException(
+            status_code=status.HTTP_409_CONFLICT,
+            detail="Kundennummer ist bereits vergeben",
+        )
+
+
+@router.get("", response_model=list[CustomerResponse])
+@router.get("/", response_model=list[CustomerResponse], include_in_schema=False)
+def get_customers(
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_permission("customers.read")),
+):
+    logger.info("customers.list", extra={"actor_user_id": current_user.id})
+    return CustomerRepository.get_all(db)
+
+
+@router.get("/{customer_id}", response_model=CustomerResponse)
+def get_customer(
+    customer_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_permission("customers.read")),
+):
+    logger.info(
+        "customers.detail",
+        extra={"actor_user_id": current_user.id, "target_customer_id": customer_id},
+    )
+    return get_customer_or_404(db, customer_id)
+
+
+@router.post("", response_model=CustomerResponse, status_code=status.HTTP_201_CREATED)
+@router.post(
+    "/",
+    response_model=CustomerResponse,
+    status_code=status.HTTP_201_CREATED,
+    include_in_schema=False,
+)
+def create_customer(
+    customer: CustomerCreate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_permission("customers.create")),
+):
+    ensure_unique_customer_number(db, customer.customer_number)
+    logger.info("customers.create", extra={"actor_user_id": current_user.id})
+    return CustomerRepository.create(db, customer)
+
+
+@router.put("/{customer_id}", response_model=CustomerResponse)
+def update_customer(
+    customer_id: int,
+    customer: CustomerUpdate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_permission("customers.update")),
+):
+    db_customer = get_customer_or_404(db, customer_id)
+    ensure_unique_customer_number(db, customer.customer_number, customer_id)
+    logger.info(
+        "customers.update",
+        extra={"actor_user_id": current_user.id, "target_customer_id": customer_id},
+    )
+    return CustomerRepository.update(db, db_customer, customer)
+
+
+@router.delete("/{customer_id}", status_code=status.HTTP_204_NO_CONTENT)
+def delete_customer(
+    customer_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_permission("customers.delete")),
+):
+    db_customer = get_customer_or_404(db, customer_id)
+    logger.info(
+        "customers.delete",
+        extra={"actor_user_id": current_user.id, "target_customer_id": customer_id},
+    )
+    CustomerRepository.delete(db, db_customer)
+    return Response(status_code=status.HTTP_204_NO_CONTENT)
+
+
+@router.get("/{customer_id}/contacts", response_model=list[CustomerContactResponse])
+def get_customer_contacts(
+    customer_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_permission("customers.read")),
+):
+    get_customer_or_404(db, customer_id)
+    logger.info(
+        "customers.contacts.list",
+        extra={"actor_user_id": current_user.id, "target_customer_id": customer_id},
+    )
+    return CustomerRepository.get_contacts(db, customer_id)
+
+
+@router.post(
+    "/{customer_id}/contacts",
+    response_model=CustomerContactResponse,
+    status_code=status.HTTP_201_CREATED,
+)
+def create_customer_contact(
+    customer_id: int,
+    contact: CustomerContactCreate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_permission("customers.update")),
+):
+    get_customer_or_404(db, customer_id)
+    logger.info(
+        "customers.contacts.create",
+        extra={"actor_user_id": current_user.id, "target_customer_id": customer_id},
+    )
+    return CustomerRepository.create_contact(db, customer_id, contact)
+
+
+@router.put("/{customer_id}/contacts/{contact_id}", response_model=CustomerContactResponse)
+def update_customer_contact(
+    customer_id: int,
+    contact_id: int,
+    contact: CustomerContactUpdate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_permission("customers.update")),
+):
+    get_customer_or_404(db, customer_id)
+    db_contact = get_contact_or_404(db, customer_id, contact_id)
+    logger.info(
+        "customers.contacts.update",
+        extra={
+            "actor_user_id": current_user.id,
+            "target_customer_id": customer_id,
+            "target_contact_id": contact_id,
+        },
+    )
+    return CustomerRepository.update_contact(db, db_contact, contact)
+
+
+@router.delete("/{customer_id}/contacts/{contact_id}", status_code=status.HTTP_204_NO_CONTENT)
+def delete_customer_contact(
+    customer_id: int,
+    contact_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_permission("customers.update")),
+):
+    get_customer_or_404(db, customer_id)
+    db_contact = get_contact_or_404(db, customer_id, contact_id)
+    logger.info(
+        "customers.contacts.delete",
+        extra={
+            "actor_user_id": current_user.id,
+            "target_customer_id": customer_id,
+            "target_contact_id": contact_id,
+        },
+    )
+    CustomerRepository.delete_contact(db, db_contact)
+    return Response(status_code=status.HTTP_204_NO_CONTENT)
--- a/backend/hermes/app/api/dashboard.py
+++ b/backend/hermes/app/api/dashboard.py
@ -0,0 +1,80 @@
+import logging
+
+from fastapi import APIRouter, Depends
+from sqlalchemy import func, select
+from sqlalchemy.orm import Session
+
+from app.core.rbac import get_user_permission_names, require_permission
+from app.db.database import get_db
+from app.models.rbac import Role
+from app.models.user import User
+from app.repositories.customer_repository import CustomerRepository
+from app.repositories.user_repository import UserRepository
+from app.schemas.dashboard import DashboardSummary, EmptyWidget, MetricCard
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter(
+    prefix="/dashboard",
+    tags=["Dashboard"],
+)
+
+
+@router.get("/summary", response_model=DashboardSummary)
+def get_dashboard_summary(
+    db: Session = Depends(get_db),
+    current_user: User = Depends(require_permission("dashboard.read")),
+):
+    permissions = get_user_permission_names(current_user)
+    customers: list[MetricCard] = []
+    latest_customers = []
+    users: list[MetricCard] = []
+    roles: list[MetricCard] = []
+
+    if "customers.read" in permissions:
+        customers = [
+            MetricCard(label="Kunden", value=CustomerRepository.count_all(db)),
+            MetricCard(label="Aktive Kunden", value=CustomerRepository.count_active(db)),
+            MetricCard(label="Neue Kunden", value=CustomerRepository.count_recent(db)),
+        ]
+        latest_customers = CustomerRepository.get_latest(db)
+
+    if "users.read" in permissions:
+        all_users = UserRepository.get_all(db)
+        users = [
+            MetricCard(label="Benutzer", value=len(all_users)),
+            MetricCard(label="Aktive Benutzer", value=len([user for user in all_users if user.is_active])),
+        ]
+
+    if "roles.read" in permissions:
+        roles = [
+            MetricCard(
+                label="Rollen",
+                value=db.scalar(select(func.count(Role.id))) or 0,
+            )
+        ]
+
+    logger.info("dashboard.summary", extra={"actor_user_id": current_user.id})
+
+    return DashboardSummary(
+        customers=customers,
+        latest_customers=latest_customers,
+        users=users,
+        roles=roles,
+        activities=EmptyWidget(
+            title="Letzte Aktivitäten",
+            message="Noch keine Aktivitäten vorhanden.",
+        ),
+        tasks=EmptyWidget(
+            title="Offene Aufgaben",
+            message="Noch keine Aufgaben vorhanden.",
+        ),
+        tickets=EmptyWidget(
+            title="Offene Tickets",
+            message="Noch keine Tickets vorhanden.",
+        ),
+        projects=EmptyWidget(
+            title="Projekte",
+            message="Noch keine Projektdaten vorhanden.",
+        ),
+    )
--- a/backend/hermes/app/db/database.py
+++ b/backend/hermes/app/db/database.py
@ -21,6 +21,7 @@ class Base(DeclarativeBase):

 # <<< HIER IMPORTIEREN >>>
 import app.models.rbac
+import app.models.customer
 import app.models.user


--- a/backend/hermes/app/main.py
+++ b/backend/hermes/app/main.py
@ -9,6 +9,8 @@ from starlette import status
 from starlette.requests import Request

 from app.api.auth import router as auth_router
+from app.api.customers import router as customers_router
+from app.api.dashboard import router as dashboard_router
 from app.api.permissions import router as permissions_router
 from app.api.roles import router as roles_router
 from app.api.users import router as users_router
@ -26,6 +28,8 @@ app.include_router(auth_router)
 app.include_router(users_router)
 app.include_router(roles_router)
 app.include_router(permissions_router)
+app.include_router(customers_router)
+app.include_router(dashboard_router)

 logger = logging.getLogger(__name__)

--- a/backend/hermes/app/models/customer.py
+++ b/backend/hermes/app/models/customer.py
@ -0,0 +1,92 @@
+from datetime import datetime
+
+from sqlalchemy import Boolean, DateTime, ForeignKey, String, Text, func
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.db.database import Base
+
+
+class Customer(Base):
+    __tablename__ = "customers"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    customer_number: Mapped[str] = mapped_column(String(50), unique=True, index=True)
+    company_name: Mapped[str] = mapped_column(String(255), index=True)
+    legal_name: Mapped[str] = mapped_column(String(255), default="", server_default="")
+    customer_type: Mapped[str] = mapped_column(String(50), index=True)
+    status: Mapped[str] = mapped_column(String(50), index=True)
+    industry: Mapped[str] = mapped_column(String(120), default="", server_default="")
+    website: Mapped[str] = mapped_column(String(255), default="", server_default="")
+    email: Mapped[str] = mapped_column(String(255), default="", server_default="")
+    phone: Mapped[str] = mapped_column(String(80), default="", server_default="")
+    tax_number: Mapped[str] = mapped_column(String(120), default="", server_default="")
+    vat_id: Mapped[str] = mapped_column(String(120), default="", server_default="")
+    notes: Mapped[str] = mapped_column(Text, default="", server_default="")
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+        onupdate=func.now(),
+    )
+
+    addresses: Mapped[list["CustomerAddress"]] = relationship(
+        back_populates="customer",
+        cascade="all, delete-orphan",
+        lazy="selectin",
+    )
+    contacts: Mapped[list["CustomerContact"]] = relationship(
+        back_populates="customer",
+        cascade="all, delete-orphan",
+        lazy="selectin",
+    )
+
+
+class CustomerAddress(Base):
+    __tablename__ = "customer_addresses"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    customer_id: Mapped[int] = mapped_column(
+        ForeignKey("customers.id", ondelete="CASCADE"),
+        index=True,
+    )
+    type: Mapped[str] = mapped_column(String(50), index=True)
+    street: Mapped[str] = mapped_column(String(255), default="", server_default="")
+    postal_code: Mapped[str] = mapped_column(String(30), default="", server_default="")
+    city: Mapped[str] = mapped_column(String(120), default="", server_default="")
+    state: Mapped[str] = mapped_column(String(120), default="", server_default="")
+    country: Mapped[str] = mapped_column(String(120), default="Deutschland", server_default="Deutschland")
+    is_primary: Mapped[bool] = mapped_column(Boolean, default=False, server_default="false")
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+        onupdate=func.now(),
+    )
+
+    customer: Mapped[Customer] = relationship(back_populates="addresses")
+
+
+class CustomerContact(Base):
+    __tablename__ = "customer_contacts"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    customer_id: Mapped[int] = mapped_column(
+        ForeignKey("customers.id", ondelete="CASCADE"),
+        index=True,
+    )
+    first_name: Mapped[str] = mapped_column(String(100), default="", server_default="")
+    last_name: Mapped[str] = mapped_column(String(100), default="", server_default="")
+    position: Mapped[str] = mapped_column(String(120), default="", server_default="")
+    email: Mapped[str] = mapped_column(String(255), default="", server_default="")
+    phone: Mapped[str] = mapped_column(String(80), default="", server_default="")
+    mobile: Mapped[str] = mapped_column(String(80), default="", server_default="")
+    is_primary: Mapped[bool] = mapped_column(Boolean, default=False, server_default="false")
+    notes: Mapped[str] = mapped_column(Text, default="", server_default="")
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+        onupdate=func.now(),
+    )
+
+    customer: Mapped[Customer] = relationship(back_populates="contacts")
--- a/backend/hermes/app/repositories/customer_repository.py
+++ b/backend/hermes/app/repositories/customer_repository.py
@ -0,0 +1,269 @@
+from datetime import UTC, datetime, timedelta
+
+from sqlalchemy import func, select
+from sqlalchemy.orm import Session, selectinload
+
+from app.models.customer import Customer, CustomerAddress, CustomerContact
+from app.schemas.customer import (
+    CustomerAddressCreate,
+    CustomerAddressUpdate,
+    CustomerContactCreate,
+    CustomerContactUpdate,
+    CustomerCreate,
+    CustomerUpdate,
+)
+
+
+def _email(value: object) -> str:
+    return "" if value is None else str(value)
+
+
+def _url(value: object) -> str:
+    return "" if value is None else str(value)
+
+
+class CustomerRepository:
+    @staticmethod
+    def get_all(db: Session) -> list[Customer]:
+        return list(
+            db.scalars(
+                select(Customer)
+                .options(
+                    selectinload(Customer.addresses),
+                    selectinload(Customer.contacts),
+                )
+                .order_by(Customer.created_at.desc())
+            )
+        )
+
+    @staticmethod
+    def get_by_id(db: Session, customer_id: int) -> Customer | None:
+        return db.scalar(
+            select(Customer)
+            .where(Customer.id == customer_id)
+            .options(
+                selectinload(Customer.addresses),
+                selectinload(Customer.contacts),
+            )
+        )
+
+    @staticmethod
+    def get_by_number(db: Session, customer_number: str) -> Customer | None:
+        return db.scalar(select(Customer).where(Customer.customer_number == customer_number))
+
+    @staticmethod
+    def find_number_conflict(
+        db: Session,
+        *,
+        customer_number: str,
+        exclude_customer_id: int | None = None,
+    ) -> Customer | None:
+        query = select(Customer).where(Customer.customer_number == customer_number)
+        if exclude_customer_id is not None:
+            query = query.where(Customer.id != exclude_customer_id)
+        return db.scalar(query)
+
+    @staticmethod
+    def count_all(db: Session) -> int:
+        return db.scalar(select(func.count(Customer.id))) or 0
+
+    @staticmethod
+    def count_active(db: Session) -> int:
+        return db.scalar(select(func.count(Customer.id)).where(Customer.status == "active")) or 0
+
+    @staticmethod
+    def count_recent(db: Session, days: int = 30) -> int:
+        since = datetime.now(UTC) - timedelta(days=days)
+        return db.scalar(
+            select(func.count(Customer.id))
+            .where(Customer.created_at >= since)
+        ) or 0
+
+    @staticmethod
+    def get_latest(db: Session, limit: int = 5) -> list[Customer]:
+        return list(
+            db.scalars(
+                select(Customer)
+                .options(selectinload(Customer.addresses), selectinload(Customer.contacts))
+                .order_by(Customer.created_at.desc())
+                .limit(limit)
+            )
+        )
+
+    @staticmethod
+    def create(db: Session, customer: CustomerCreate) -> Customer:
+        db_customer = Customer(
+            customer_number=customer.customer_number,
+            company_name=customer.company_name,
+            legal_name=customer.legal_name,
+            customer_type=customer.customer_type,
+            status=customer.status,
+            industry=customer.industry,
+            website=_url(customer.website),
+            email=_email(customer.email),
+            phone=customer.phone,
+            tax_number=customer.tax_number,
+            vat_id=customer.vat_id,
+            notes=customer.notes,
+        )
+        db_customer.addresses = [
+            CustomerRepository._address_from_payload(address)
+            for address in customer.addresses
+        ]
+        db_customer.contacts = [
+            CustomerRepository._contact_from_payload(contact)
+            for contact in customer.contacts
+        ]
+        CustomerRepository._normalize_primary(db_customer.addresses)
+        CustomerRepository._normalize_primary(db_customer.contacts)
+
+        db.add(db_customer)
+        db.commit()
+        db.refresh(db_customer)
+
+        return CustomerRepository.get_by_id(db, db_customer.id) or db_customer
+
+    @staticmethod
+    def update(db: Session, db_customer: Customer, customer: CustomerUpdate) -> Customer:
+        db_customer.customer_number = customer.customer_number
+        db_customer.company_name = customer.company_name
+        db_customer.legal_name = customer.legal_name
+        db_customer.customer_type = customer.customer_type
+        db_customer.status = customer.status
+        db_customer.industry = customer.industry
+        db_customer.website = _url(customer.website)
+        db_customer.email = _email(customer.email)
+        db_customer.phone = customer.phone
+        db_customer.tax_number = customer.tax_number
+        db_customer.vat_id = customer.vat_id
+        db_customer.notes = customer.notes
+
+        db_customer.addresses = [
+            CustomerRepository._address_from_payload(address)
+            for address in customer.addresses
+        ]
+        CustomerRepository._normalize_primary(db_customer.addresses)
+
+        db.commit()
+        db.refresh(db_customer)
+
+        return CustomerRepository.get_by_id(db, db_customer.id) or db_customer
+
+    @staticmethod
+    def delete(db: Session, db_customer: Customer) -> None:
+        db.delete(db_customer)
+        db.commit()
+
+    @staticmethod
+    def get_contacts(db: Session, customer_id: int) -> list[CustomerContact]:
+        return list(
+            db.scalars(
+                select(CustomerContact)
+                .where(CustomerContact.customer_id == customer_id)
+                .order_by(CustomerContact.is_primary.desc(), CustomerContact.last_name)
+            )
+        )
+
+    @staticmethod
+    def get_contact_by_id(
+        db: Session,
+        customer_id: int,
+        contact_id: int,
+    ) -> CustomerContact | None:
+        return db.scalar(
+            select(CustomerContact)
+            .where(CustomerContact.customer_id == customer_id)
+            .where(CustomerContact.id == contact_id)
+        )
+
+    @staticmethod
+    def create_contact(
+        db: Session,
+        customer_id: int,
+        contact: CustomerContactCreate,
+    ) -> CustomerContact:
+        db_contact = CustomerRepository._contact_from_payload(contact)
+        db_contact.customer_id = customer_id
+        db.add(db_contact)
+        db.flush()
+
+        if db_contact.is_primary:
+            CustomerRepository._clear_other_primary_contacts(db, customer_id, db_contact.id)
+
+        db.commit()
+        db.refresh(db_contact)
+        return db_contact
+
+    @staticmethod
+    def update_contact(
+        db: Session,
+        db_contact: CustomerContact,
+        contact: CustomerContactUpdate,
+    ) -> CustomerContact:
+        db_contact.first_name = contact.first_name
+        db_contact.last_name = contact.last_name
+        db_contact.position = contact.position
+        db_contact.email = _email(contact.email)
+        db_contact.phone = contact.phone
+        db_contact.mobile = contact.mobile
+        db_contact.is_primary = contact.is_primary
+        db_contact.notes = contact.notes
+
+        if db_contact.is_primary:
+            CustomerRepository._clear_other_primary_contacts(db, db_contact.customer_id, db_contact.id)
+
+        db.commit()
+        db.refresh(db_contact)
+        return db_contact
+
+    @staticmethod
+    def delete_contact(db: Session, db_contact: CustomerContact) -> None:
+        db.delete(db_contact)
+        db.commit()
+
+    @staticmethod
+    def _address_from_payload(address: CustomerAddressCreate | CustomerAddressUpdate) -> CustomerAddress:
+        return CustomerAddress(
+            type=address.type,
+            street=address.street,
+            postal_code=address.postal_code,
+            city=address.city,
+            state=address.state,
+            country=address.country,
+            is_primary=address.is_primary,
+        )
+
+    @staticmethod
+    def _contact_from_payload(contact: CustomerContactCreate | CustomerContactUpdate) -> CustomerContact:
+        return CustomerContact(
+            first_name=contact.first_name,
+            last_name=contact.last_name,
+            position=contact.position,
+            email=_email(contact.email),
+            phone=contact.phone,
+            mobile=contact.mobile,
+            is_primary=contact.is_primary,
+            notes=contact.notes,
+        )
+
+    @staticmethod
+    def _normalize_primary(items: list[CustomerAddress] | list[CustomerContact]) -> None:
+        primary_seen = False
+        for item in items:
+            if item.is_primary and not primary_seen:
+                primary_seen = True
+            elif item.is_primary:
+                item.is_primary = False
+
+        if items and not primary_seen:
+            items[0].is_primary = True
+
+    @staticmethod
+    def _clear_other_primary_contacts(db: Session, customer_id: int, contact_id: int) -> None:
+        contacts = db.scalars(
+            select(CustomerContact)
+            .where(CustomerContact.customer_id == customer_id)
+            .where(CustomerContact.id != contact_id)
+        )
+        for contact in contacts:
+            contact.is_primary = False
--- a/backend/hermes/app/schemas/customer.py
+++ b/backend/hermes/app/schemas/customer.py
@ -0,0 +1,131 @@
+from datetime import datetime
+from typing import Literal
+
+from pydantic import BaseModel, ConfigDict, EmailStr, Field, HttpUrl, field_validator
+
+CustomerStatus = Literal["lead", "active", "inactive", "blocked", "archived"]
+CustomerType = Literal["company", "private", "public_sector", "partner", "supplier"]
+AddressType = Literal["billing", "shipping", "primary", "other"]
+
+
+def normalize_optional_text(value: object) -> str:
+    if value is None:
+        return ""
+    return str(value).strip()
+
+
+class CustomerAddressBase(BaseModel):
+    type: AddressType = "primary"
+    street: str = Field(default="", max_length=255)
+    postal_code: str = Field(default="", max_length=30)
+    city: str = Field(default="", max_length=120)
+    state: str = Field(default="", max_length=120)
+    country: str = Field(default="Deutschland", max_length=120)
+    is_primary: bool = False
+
+    @field_validator("street", "postal_code", "city", "state", "country", mode="before")
+    @classmethod
+    def normalize_text(cls, value: object) -> str:
+        return normalize_optional_text(value)
+
+
+class CustomerAddressCreate(CustomerAddressBase):
+    pass
+
+
+class CustomerAddressUpdate(CustomerAddressBase):
+    pass
+
+
+class CustomerAddressResponse(CustomerAddressBase):
+    id: int
+    customer_id: int
+    created_at: datetime
+    updated_at: datetime
+
+    model_config = ConfigDict(from_attributes=True)
+
+
+class CustomerContactBase(BaseModel):
+    first_name: str = Field(default="", max_length=100)
+    last_name: str = Field(default="", max_length=100)
+    position: str = Field(default="", max_length=120)
+    email: EmailStr | None = None
+    phone: str = Field(default="", max_length=80)
+    mobile: str = Field(default="", max_length=80)
+    is_primary: bool = False
+    notes: str = ""
+
+    @field_validator("first_name", "last_name", "position", "phone", "mobile", "notes", mode="before")
+    @classmethod
+    def normalize_text(cls, value: object) -> str:
+        return normalize_optional_text(value)
+
+
+class CustomerContactCreate(CustomerContactBase):
+    pass
+
+
+class CustomerContactUpdate(CustomerContactBase):
+    pass
+
+
+class CustomerContactResponse(CustomerContactBase):
+    id: int
+    customer_id: int
+    email: str
+    created_at: datetime
+    updated_at: datetime
+
+    model_config = ConfigDict(from_attributes=True)
+
+
+class CustomerBase(BaseModel):
+    customer_number: str = Field(min_length=1, max_length=50)
+    company_name: str = Field(min_length=1, max_length=255)
+    legal_name: str = Field(default="", max_length=255)
+    customer_type: CustomerType
+    status: CustomerStatus
+    industry: str = Field(default="", max_length=120)
+    website: HttpUrl | None = None
+    email: EmailStr | None = None
+    phone: str = Field(default="", max_length=80)
+    tax_number: str = Field(default="", max_length=120)
+    vat_id: str = Field(default="", max_length=120)
+    notes: str = ""
+
+    @field_validator(
+        "customer_number",
+        "company_name",
+        "legal_name",
+        "industry",
+        "phone",
+        "tax_number",
+        "vat_id",
+        "notes",
+        mode="before",
+    )
+    @classmethod
+    def normalize_text(cls, value: object) -> str:
+        return normalize_optional_text(value)
+
+
+class CustomerCreate(CustomerBase):
+    addresses: list[CustomerAddressCreate] = Field(default_factory=list)
+    contacts: list[CustomerContactCreate] = Field(default_factory=list)
+
+
+class CustomerUpdate(CustomerBase):
+    addresses: list[CustomerAddressUpdate] = Field(default_factory=list)
+
+
+class CustomerResponse(CustomerBase):
+    id: int
+    website: str
+    email: str
+    addresses: list[CustomerAddressResponse]
+    contacts: list[CustomerContactResponse]
+    created_at: datetime
+    updated_at: datetime
+
+    model_config = ConfigDict(from_attributes=True)
--- a/backend/hermes/app/schemas/dashboard.py
+++ b/backend/hermes/app/schemas/dashboard.py
@ -0,0 +1,24 @@
+from pydantic import BaseModel
+
+from app.schemas.customer import CustomerResponse
+
+
+class MetricCard(BaseModel):
+    label: str
+    value: int
+
+
+class EmptyWidget(BaseModel):
+    title: str
+    message: str
+
+
+class DashboardSummary(BaseModel):
+    customers: list[MetricCard] = []
+    latest_customers: list[CustomerResponse] = []
+    users: list[MetricCard] = []
+    roles: list[MetricCard] = []
+    activities: EmptyWidget
+    tasks: EmptyWidget
+    tickets: EmptyWidget
+    projects: EmptyWidget
--- a/frontend/athena/app/api/customers/[id]/contacts/[contactId]/route.ts
+++ b/frontend/athena/app/api/customers/[id]/contacts/[contactId]/route.ts
@ -0,0 +1,36 @@
+import { NextRequest } from "next/server";
+
+import { proxyHermesRequest } from "@/lib/server/hermes-proxy";
+import { assertSameOrigin } from "@/lib/server/request-guards";
+
+type Params = {
+  params: Promise<{
+    id: string;
+    contactId: string;
+  }>;
+};
+
+async function proxyContactRequest(request: NextRequest, { params }: Params) {
+  const { id, contactId } = await params;
+  return proxyHermesRequest(request, `/customers/${id}/contacts/${contactId}`);
+}
+
+export async function PUT(request: NextRequest, context: Params) {
+  const originError = assertSameOrigin(request);
+
+  if (originError) {
+    return originError;
+  }
+
+  return proxyContactRequest(request, context);
+}
+
+export async function DELETE(request: NextRequest, context: Params) {
+  const originError = assertSameOrigin(request);
+
+  if (originError) {
+    return originError;
+  }
+
+  return proxyContactRequest(request, context);
+}
--- a/frontend/athena/app/api/customers/[id]/contacts/route.ts
+++ b/frontend/athena/app/api/customers/[id]/contacts/route.ts
@ -0,0 +1,29 @@
+import { NextRequest } from "next/server";
+
+import { proxyHermesRequest } from "@/lib/server/hermes-proxy";
+import { assertSameOrigin } from "@/lib/server/request-guards";
+
+type Params = {
+  params: Promise<{
+    id: string;
+  }>;
+};
+
+async function proxyContactsRequest(request: NextRequest, { params }: Params) {
+  const { id } = await params;
+  return proxyHermesRequest(request, `/customers/${id}/contacts`);
+}
+
+export async function GET(request: NextRequest, context: Params) {
+  return proxyContactsRequest(request, context);
+}
+
+export async function POST(request: NextRequest, context: Params) {
+  const originError = assertSameOrigin(request);
+
+  if (originError) {
+    return originError;
+  }
+
+  return proxyContactsRequest(request, context);
+}
--- a/frontend/athena/app/api/customers/[id]/route.ts
+++ b/frontend/athena/app/api/customers/[id]/route.ts
@ -0,0 +1,39 @@
+import { NextRequest } from "next/server";
+
+import { proxyHermesRequest } from "@/lib/server/hermes-proxy";
+import { assertSameOrigin } from "@/lib/server/request-guards";
+
+type Params = {
+  params: Promise<{
+    id: string;
+  }>;
+};
+
+async function proxyCustomerRequest(request: NextRequest, { params }: Params) {
+  const { id } = await params;
+  return proxyHermesRequest(request, `/customers/${id}`);
+}
+
+export async function GET(request: NextRequest, context: Params) {
+  return proxyCustomerRequest(request, context);
+}
+
+export async function PUT(request: NextRequest, context: Params) {
+  const originError = assertSameOrigin(request);
+
+  if (originError) {
+    return originError;
+  }
+
+  return proxyCustomerRequest(request, context);
+}
+
+export async function DELETE(request: NextRequest, context: Params) {
+  const originError = assertSameOrigin(request);
+
+  if (originError) {
+    return originError;
+  }
+
+  return proxyCustomerRequest(request, context);
+}
--- a/frontend/athena/app/api/customers/route.ts
+++ b/frontend/athena/app/api/customers/route.ts
@ -0,0 +1,18 @@
+import { NextRequest } from "next/server";
+
+import { proxyHermesRequest } from "@/lib/server/hermes-proxy";
+import { assertSameOrigin } from "@/lib/server/request-guards";
+
+export async function GET(request: NextRequest) {
+  return proxyHermesRequest(request, `/customers${request.nextUrl.search}`);
+}
+
+export async function POST(request: NextRequest) {
+  const originError = assertSameOrigin(request);
+
+  if (originError) {
+    return originError;
+  }
+
+  return proxyHermesRequest(request, "/customers");
+}
--- a/frontend/athena/app/api/dashboard/summary/route.ts
+++ b/frontend/athena/app/api/dashboard/summary/route.ts
@ -0,0 +1,7 @@
+import { NextRequest } from "next/server";
+
+import { proxyHermesRequest } from "@/lib/server/hermes-proxy";
+
+export async function GET(request: NextRequest) {
+  return proxyHermesRequest(request, "/dashboard/summary");
+}
--- a/frontend/athena/app/customers/[id]/page.tsx
+++ b/frontend/athena/app/customers/[id]/page.tsx
@ -0,0 +1,345 @@
+"use client";
+
+import { useCallback, useEffect, useState } from "react";
+import Link from "next/link";
+import { useParams, useRouter } from "next/navigation";
+import { ArrowLeft, Edit, Plus, Trash2 } from "lucide-react";
+
+import ConfirmDialog from "@/components/common/ConfirmDialog";
+import DetailSection from "@/components/common/DetailSection";
+import { Button } from "@/components/ui/button";
+import CustomerContactFormDialog from "@/components/customers/CustomerContactFormDialog";
+import CustomerFormDialog from "@/components/customers/CustomerFormDialog";
+import CustomerStatusBadge from "@/components/customers/CustomerStatusBadge";
+import { api } from "@/lib/api";
+import { hasPermission } from "@/lib/permissions";
+import type { CurrentUser } from "@/types/rbac";
+import type { Customer, CustomerContact, CustomerContactPayload, CustomerPayload } from "@/types/customer";
+
+function getErrorMessage(error: unknown) {
+  if (typeof error === "object" && error !== null && "response" in error) {
+    const response = (error as { response?: { data?: { detail?: string } } }).response;
+    return response?.data?.detail ?? "Aktion konnte nicht abgeschlossen werden";
+  }
+  return "Aktion konnte nicht abgeschlossen werden";
+}
+
+function formatDateTime(value: string) {
+  return new Intl.DateTimeFormat("de-DE", {
+    dateStyle: "medium",
+    timeStyle: "short",
+  }).format(new Date(value));
+}
+
+export default function CustomerDetailPage() {
+  const params = useParams<{ id: string }>();
+  const router = useRouter();
+  const [customer, setCustomer] = useState<Customer | null>(null);
+  const [currentUser, setCurrentUser] = useState<CurrentUser | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState("");
+  const [pending, setPending] = useState(false);
+  const [formOpen, setFormOpen] = useState(false);
+  const [formError, setFormError] = useState("");
+  const [contactOpen, setContactOpen] = useState(false);
+  const [contactError, setContactError] = useState("");
+  const [selectedContact, setSelectedContact] = useState<CustomerContact | null>(null);
+  const [deleteContact, setDeleteContact] = useState<CustomerContact | null>(null);
+  const [deleteCustomerOpen, setDeleteCustomerOpen] = useState(false);
+  const [deleteError, setDeleteError] = useState("");
+
+  const loadCustomer = useCallback(async () => {
+    try {
+      const [customerResponse, meResponse] = await Promise.all([
+        api.get<Customer>(`/customers/${params.id}`),
+        api.get<CurrentUser>("/me"),
+      ]);
+      setCustomer(customerResponse.data);
+      setCurrentUser(meResponse.data);
+    } catch (err) {
+      setError(getErrorMessage(err));
+    } finally {
+      setLoading(false);
+    }
+  }, [params.id]);
+
+  useEffect(() => {
+    queueMicrotask(() => {
+      void loadCustomer();
+    });
+  }, [loadCustomer]);
+
+  async function saveCustomer(payload: CustomerPayload) {
+    if (!customer) {
+      return;
+    }
+    setPending(true);
+    setFormError("");
+    try {
+      const response = await api.put<Customer>(`/customers/${customer.id}`, payload);
+      setCustomer(response.data);
+      setFormOpen(false);
+    } catch (err) {
+      setFormError(getErrorMessage(err));
+    } finally {
+      setPending(false);
+    }
+  }
+
+  function openContactDialog(contact: CustomerContact | null) {
+    setSelectedContact(contact);
+    setContactError("");
+    setContactOpen(true);
+  }
+
+  async function saveContact(payload: CustomerContactPayload) {
+    if (!customer) {
+      return;
+    }
+    setPending(true);
+    setContactError("");
+    try {
+      if (selectedContact) {
+        await api.put<CustomerContact>(`/customers/${customer.id}/contacts/${selectedContact.id}`, payload);
+      } else {
+        await api.post<CustomerContact>(`/customers/${customer.id}/contacts`, payload);
+      }
+      const response = await api.get<Customer>(`/customers/${customer.id}`);
+      setCustomer(response.data);
+      setContactOpen(false);
+    } catch (err) {
+      setContactError(getErrorMessage(err));
+    } finally {
+      setPending(false);
+    }
+  }
+
+  async function confirmContactDelete() {
+    if (!customer || !deleteContact) {
+      return;
+    }
+    setPending(true);
+    setDeleteError("");
+    try {
+      await api.delete(`/customers/${customer.id}/contacts/${deleteContact.id}`);
+      const response = await api.get<Customer>(`/customers/${customer.id}`);
+      setCustomer(response.data);
+      setDeleteContact(null);
+    } catch (err) {
+      setDeleteError(getErrorMessage(err));
+    } finally {
+      setPending(false);
+    }
+  }
+
+  async function confirmCustomerDelete() {
+    if (!customer) {
+      return;
+    }
+    setPending(true);
+    setDeleteError("");
+    try {
+      await api.delete(`/customers/${customer.id}`);
+      router.push("/customers");
+    } catch (err) {
+      setDeleteError(getErrorMessage(err));
+    } finally {
+      setPending(false);
+    }
+  }
+
+  if (loading) {
+    return <div className="rounded-lg border bg-white p-8 text-slate-500">Kunde wird geladen...</div>;
+  }
+
+  if (error || !customer) {
+    return (
+      <div className="space-y-4">
+        <Link href="/customers" className="inline-flex items-center gap-2 text-sm text-slate-500 hover:text-slate-900">
+          <ArrowLeft size={16} />
+          Zurück zur Kundenliste
+        </Link>
+        <div className="rounded-lg border bg-white p-8 text-red-600">{error || "Kunde nicht gefunden"}</div>
+      </div>
+    );
+  }
+
+  return (
+    <div className="space-y-6">
+      <div className="flex flex-col gap-4 lg:flex-row lg:items-center lg:justify-between">
+        <div>
+          <Link href="/customers" className="inline-flex items-center gap-2 text-sm text-slate-500 hover:text-slate-900">
+            <ArrowLeft size={16} />
+            Zurück zur Kundenliste
+          </Link>
+          <div className="mt-3 flex items-center gap-3">
+            <h1 className="text-3xl font-bold text-slate-950">{customer.company_name}</h1>
+            <CustomerStatusBadge status={customer.status} />
+          </div>
+          <p className="mt-1 text-sm text-slate-500">{customer.customer_number}</p>
+        </div>
+
+        <div className="flex gap-2">
+          {hasPermission(currentUser, "customers.update") && (
+            <Button type="button" onClick={() => setFormOpen(true)}>
+              <Edit size={16} />
+              Bearbeiten
+            </Button>
+          )}
+          {hasPermission(currentUser, "customers.delete") && (
+            <Button type="button" variant="destructive" onClick={() => setDeleteCustomerOpen(true)}>
+              <Trash2 size={16} />
+              Löschen
+            </Button>
+          )}
+        </div>
+      </div>
+
+      <DetailSection title="Stammdaten">
+        <dl className="grid gap-5 md:grid-cols-2">
+          <Detail label="Kundennummer" value={customer.customer_number} />
+          <Detail label="Typ" value={customer.customer_type} />
+          <Detail label="Rechtlicher Name" value={customer.legal_name || "-"} />
+          <Detail label="Branche" value={customer.industry || "-"} />
+          <Detail label="E-Mail" value={customer.email || "-"} />
+          <Detail label="Telefon" value={customer.phone || "-"} />
+          <Detail label="Website" value={customer.website || "-"} />
+          <Detail label="USt-ID" value={customer.vat_id || "-"} />
+        </dl>
+      </DetailSection>
+
+      <DetailSection title="Adressen">
+        {customer.addresses.length === 0 ? (
+          <p className="text-sm text-slate-500">Noch keine Adressen vorhanden.</p>
+        ) : (
+          <div className="grid gap-3 md:grid-cols-2">
+            {customer.addresses.map((address) => (
+              <div key={address.id} className="rounded-lg border p-4 text-sm">
+                <div className="mb-2 flex items-center justify-between">
+                  <span className="font-medium capitalize">{address.type}</span>
+                  {address.is_primary && <span className="rounded-full bg-slate-100 px-2 py-1 text-xs">Primär</span>}
+                </div>
+                <p>{address.street || "-"}</p>
+                <p>{address.postal_code} {address.city}</p>
+                <p>{address.state}</p>
+                <p>{address.country}</p>
+              </div>
+            ))}
+          </div>
+        )}
+      </DetailSection>
+
+      <DetailSection
+        title="Ansprechpartner"
+        actions={hasPermission(currentUser, "customers.update") && (
+          <Button type="button" size="sm" onClick={() => openContactDialog(null)}>
+            <Plus size={16} />
+            Ansprechpartner
+          </Button>
+        )}
+      >
+        {customer.contacts.length === 0 ? (
+          <p className="text-sm text-slate-500">Noch keine Ansprechpartner vorhanden.</p>
+        ) : (
+          <div className="grid gap-3 md:grid-cols-2">
+            {customer.contacts.map((contact) => (
+              <div key={contact.id} className="rounded-lg border p-4 text-sm">
+                <div className="mb-2 flex items-center justify-between gap-3">
+                  <div>
+                    <p className="font-medium text-slate-950">{contact.first_name} {contact.last_name}</p>
+                    <p className="text-slate-500">{contact.position || "-"}</p>
+                  </div>
+                  {contact.is_primary && <span className="rounded-full bg-slate-100 px-2 py-1 text-xs">Primär</span>}
+                </div>
+                <p>{contact.email || "-"}</p>
+                <p>{contact.phone || contact.mobile || "-"}</p>
+                {hasPermission(currentUser, "customers.update") && (
+                  <div className="mt-3 flex gap-2">
+                    <Button type="button" variant="outline" size="sm" onClick={() => openContactDialog(contact)}>
+                      Bearbeiten
+                    </Button>
+                    <Button type="button" variant="destructive" size="sm" onClick={() => setDeleteContact(contact)}>
+                      Löschen
+                    </Button>
+                  </div>
+                )}
+              </div>
+            ))}
+          </div>
+        )}
+      </DetailSection>
+
+      <DetailSection title="Notizen">
+        <p className="whitespace-pre-wrap text-sm text-slate-700">{customer.notes || "Noch keine Notizen vorhanden."}</p>
+      </DetailSection>
+
+      <DetailSection title="Metadaten">
+        <dl className="grid gap-5 md:grid-cols-2">
+          <Detail label="Erstellt" value={formatDateTime(customer.created_at)} />
+          <Detail label="Aktualisiert" value={formatDateTime(customer.updated_at)} />
+        </dl>
+      </DetailSection>
+
+      <CustomerFormDialog
+        open={formOpen}
+        customer={customer}
+        pending={pending}
+        serverError={formError}
+        onOpenChange={setFormOpen}
+        onSubmit={saveCustomer}
+      />
+
+      <CustomerContactFormDialog
+        open={contactOpen}
+        contact={selectedContact}
+        pending={pending}
+        serverError={contactError}
+        onOpenChange={setContactOpen}
+        onSubmit={saveContact}
+      />
+
+      <ConfirmDialog
+        open={Boolean(deleteContact)}
+        title="Ansprechpartner löschen"
+        description="Möchten Sie den Ansprechpartner wirklich löschen?"
+        pending={pending}
+        onOpenChange={(open) => {
+          if (!open) {
+            setDeleteContact(null);
+            setDeleteError("");
+          }
+        }}
+        onConfirm={confirmContactDelete}
+      >
+        {deleteContact && <p className="text-sm font-medium">{deleteContact.first_name} {deleteContact.last_name}</p>}
+        {deleteError && <p className="mt-2 text-sm text-red-600">{deleteError}</p>}
+      </ConfirmDialog>
+
+      <ConfirmDialog
+        open={deleteCustomerOpen}
+        title="Kunde löschen"
+        description="Möchten Sie den Kunden wirklich löschen?"
+        pending={pending}
+        onOpenChange={(open) => {
+          setDeleteCustomerOpen(open);
+          if (!open) {
+            setDeleteError("");
+          }
+        }}
+        onConfirm={confirmCustomerDelete}
+      >
+        <p className="text-sm font-medium">{customer.customer_number} · {customer.company_name}</p>
+        {deleteError && <p className="mt-2 text-sm text-red-600">{deleteError}</p>}
+      </ConfirmDialog>
+    </div>
+  );
+}
+
+function Detail({ label, value }: { label: string; value: string }) {
+  return (
+    <div>
+      <dt className="text-sm text-slate-500">{label}</dt>
+      <dd className="mt-1 font-medium text-slate-950">{value}</dd>
+    </div>
+  );
+}
--- a/frontend/athena/app/customers/page.tsx
+++ b/frontend/athena/app/customers/page.tsx
@ -0,0 +1,309 @@
+"use client";
+
+import { useCallback, useEffect, useMemo, useState } from "react";
+import Link from "next/link";
+import { Edit, Eye, Plus, Trash2 } from "lucide-react";
+
+import ConfirmDialog from "@/components/common/ConfirmDialog";
+import DataTable, { type DataTableColumn } from "@/components/common/DataTable";
+import SearchInput from "@/components/common/SearchInput";
+import { Button, buttonVariants } from "@/components/ui/button";
+import CustomerFormDialog from "@/components/customers/CustomerFormDialog";
+import CustomerStatusBadge from "@/components/customers/CustomerStatusBadge";
+import { api } from "@/lib/api";
+import { hasPermission } from "@/lib/permissions";
+import type { CurrentUser } from "@/types/rbac";
+import type { Customer, CustomerPayload, CustomerStatus, CustomerType } from "@/types/customer";
+
+const pageSize = 10;
+
+function getErrorMessage(error: unknown) {
+  if (typeof error === "object" && error !== null && "response" in error) {
+    const response = (error as { response?: { data?: { detail?: string } } }).response;
+    return response?.data?.detail ?? "Aktion konnte nicht abgeschlossen werden";
+  }
+  return "Aktion konnte nicht abgeschlossen werden";
+}
+
+function formatDate(value: string) {
+  return new Intl.DateTimeFormat("de-DE", {
+    day: "2-digit",
+    month: "2-digit",
+    year: "numeric",
+  }).format(new Date(value));
+}
+
+function getPrimaryCity(customer: Customer) {
+  return customer.addresses.find((address) => address.is_primary)?.city
+    || customer.addresses[0]?.city
+    || "-";
+}
+
+function getSortableValue(customer: Customer, key: string) {
+  if (key === "city") {
+    return getPrimaryCity(customer).toLowerCase();
+  }
+  const value = customer[key as keyof Customer];
+  return typeof value === "string" ? value.toLowerCase() : value;
+}
+
+export default function CustomersPage() {
+  const [customers, setCustomers] = useState<Customer[]>([]);
+  const [currentUser, setCurrentUser] = useState<CurrentUser | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState("");
+  const [formError, setFormError] = useState("");
+  const [deleteError, setDeleteError] = useState("");
+  const [pending, setPending] = useState(false);
+  const [search, setSearch] = useState("");
+  const [statusFilter, setStatusFilter] = useState<CustomerStatus | "all">("all");
+  const [typeFilter, setTypeFilter] = useState<CustomerType | "all">("all");
+  const [sortKey, setSortKey] = useState("created_at");
+  const [sortDirection, setSortDirection] = useState<"asc" | "desc">("desc");
+  const [page, setPage] = useState(1);
+  const [formOpen, setFormOpen] = useState(false);
+  const [selectedCustomer, setSelectedCustomer] = useState<Customer | null>(null);
+  const [deleteCustomer, setDeleteCustomer] = useState<Customer | null>(null);
+
+  const loadCustomers = useCallback(async () => {
+    try {
+      const [customersResponse, meResponse] = await Promise.all([
+        api.get<Customer[]>("/customers"),
+        api.get<CurrentUser>("/me"),
+      ]);
+      setCustomers(customersResponse.data);
+      setCurrentUser(meResponse.data);
+    } catch (err) {
+      setError(getErrorMessage(err));
+    } finally {
+      setLoading(false);
+    }
+  }, []);
+
+  useEffect(() => {
+    queueMicrotask(() => {
+      void loadCustomers();
+    });
+  }, [loadCustomers]);
+
+  const filteredCustomers = useMemo(() => {
+    const term = search.trim().toLowerCase();
+
+    return customers
+      .filter((customer) => {
+        if (!term) {
+          return true;
+        }
+        return [
+          customer.customer_number,
+          customer.company_name,
+          customer.legal_name,
+          customer.industry,
+          customer.email,
+          customer.phone,
+          getPrimaryCity(customer),
+        ].some((value) => value.toLowerCase().includes(term));
+      })
+      .filter((customer) => statusFilter === "all" || customer.status === statusFilter)
+      .filter((customer) => typeFilter === "all" || customer.customer_type === typeFilter)
+      .sort((first, second) => {
+        const firstValue = getSortableValue(first, sortKey);
+        const secondValue = getSortableValue(second, sortKey);
+        if (firstValue === secondValue) {
+          return 0;
+        }
+        const result = firstValue > secondValue ? 1 : -1;
+        return sortDirection === "asc" ? result : -result;
+      });
+  }, [customers, search, sortDirection, sortKey, statusFilter, typeFilter]);
+
+  const pageCount = Math.max(1, Math.ceil(filteredCustomers.length / pageSize));
+  const currentPage = Math.min(page, pageCount);
+  const pageCustomers = filteredCustomers.slice((currentPage - 1) * pageSize, currentPage * pageSize);
+
+  const columns: DataTableColumn<Customer>[] = [
+    { key: "customer_number", label: "Kundennummer", sortable: true, render: (customer) => customer.customer_number },
+    { key: "company_name", label: "Firmenname", sortable: true, render: (customer) => <span className="font-medium text-slate-950">{customer.company_name}</span> },
+    { key: "customer_type", label: "Typ", sortable: true, render: (customer) => customer.customer_type },
+    { key: "status", label: "Status", sortable: true, render: (customer) => <CustomerStatusBadge status={customer.status} /> },
+    { key: "industry", label: "Branche", sortable: true, render: (customer) => customer.industry || "-" },
+    { key: "email", label: "E-Mail", sortable: true, render: (customer) => customer.email || "-" },
+    { key: "phone", label: "Telefon", sortable: true, render: (customer) => customer.phone || "-" },
+    { key: "city", label: "Ort", sortable: true, render: (customer) => getPrimaryCity(customer) },
+    { key: "created_at", label: "Erstellt", sortable: true, render: (customer) => formatDate(customer.created_at) },
+    {
+      key: "actions",
+      label: "Aktionen",
+      className: "px-4 py-3 text-right",
+      render: (customer) => (
+        <div className="flex justify-end gap-2">
+          <Link href={`/customers/${customer.id}`} className={buttonVariants({ variant: "ghost", size: "icon-sm" })} title="Details">
+            <Eye size={16} />
+          </Link>
+          {hasPermission(currentUser, "customers.update") && (
+            <Button type="button" variant="ghost" size="icon-sm" title="Bearbeiten" onClick={() => openEditDialog(customer)}>
+              <Edit size={16} />
+            </Button>
+          )}
+          {hasPermission(currentUser, "customers.delete") && (
+            <Button type="button" variant="destructive" size="icon-sm" title="Löschen" onClick={() => setDeleteCustomer(customer)}>
+              <Trash2 size={16} />
+            </Button>
+          )}
+        </div>
+      ),
+    },
+  ];
+
+  function handleSort(key: string) {
+    if (sortKey === key) {
+      setSortDirection((current) => (current === "asc" ? "desc" : "asc"));
+      return;
+    }
+    setSortKey(key);
+    setSortDirection("asc");
+  }
+
+  function openCreateDialog() {
+    setSelectedCustomer(null);
+    setFormError("");
+    setFormOpen(true);
+  }
+
+  function openEditDialog(customer: Customer) {
+    setSelectedCustomer(customer);
+    setFormError("");
+    setFormOpen(true);
+  }
+
+  async function saveCustomer(payload: CustomerPayload) {
+    setPending(true);
+    setFormError("");
+    try {
+      if (selectedCustomer) {
+        const response = await api.put<Customer>(`/customers/${selectedCustomer.id}`, payload);
+        setCustomers((current) => current.map((customer) => customer.id === selectedCustomer.id ? response.data : customer));
+      } else {
+        const response = await api.post<Customer>("/customers", payload);
+        setCustomers((current) => [response.data, ...current]);
+      }
+      setFormOpen(false);
+    } catch (err) {
+      setFormError(getErrorMessage(err));
+    } finally {
+      setPending(false);
+    }
+  }
+
+  async function confirmDelete() {
+    if (!deleteCustomer) {
+      return;
+    }
+    setPending(true);
+    setDeleteError("");
+    try {
+      await api.delete(`/customers/${deleteCustomer.id}`);
+      setCustomers((current) => current.filter((customer) => customer.id !== deleteCustomer.id));
+      setDeleteCustomer(null);
+    } catch (err) {
+      setDeleteError(getErrorMessage(err));
+    } finally {
+      setPending(false);
+    }
+  }
+
+  return (
+    <div className="space-y-6">
+      <div className="flex flex-col gap-4 lg:flex-row lg:items-center lg:justify-between">
+        <div>
+          <h1 className="text-3xl font-bold text-slate-950">Kunden</h1>
+          <p className="mt-1 text-sm text-slate-500">{filteredCustomers.length} von {customers.length} Kunden</p>
+        </div>
+        {hasPermission(currentUser, "customers.create") && (
+          <Button type="button" onClick={openCreateDialog}>
+            <Plus size={16} />
+            Neuer Kunde
+          </Button>
+        )}
+      </div>
+
+      <div className="flex flex-col gap-3 rounded-lg border bg-white p-4 lg:flex-row lg:items-center">
+        <SearchInput value={search} onChange={(value) => { setSearch(value); setPage(1); }} placeholder="Kunden suchen" />
+        <select value={statusFilter} onChange={(event) => { setStatusFilter(event.target.value as CustomerStatus | "all"); setPage(1); }} className="h-8 rounded-lg border border-input bg-transparent px-2.5 text-sm">
+          <option value="all">Alle Status</option>
+          <option value="lead">Lead</option>
+          <option value="active">Aktiv</option>
+          <option value="inactive">Inaktiv</option>
+          <option value="blocked">Gesperrt</option>
+          <option value="archived">Archiviert</option>
+        </select>
+        <select value={typeFilter} onChange={(event) => { setTypeFilter(event.target.value as CustomerType | "all"); setPage(1); }} className="h-8 rounded-lg border border-input bg-transparent px-2.5 text-sm">
+          <option value="all">Alle Typen</option>
+          <option value="company">Unternehmen</option>
+          <option value="private">Privat</option>
+          <option value="public_sector">Öffentlicher Sektor</option>
+          <option value="partner">Partner</option>
+          <option value="supplier">Lieferant</option>
+        </select>
+      </div>
+
+      <DataTable
+        columns={columns}
+        rows={pageCustomers}
+        rowKey={(customer) => customer.id}
+        sortKey={sortKey}
+        sortDirection={sortDirection}
+        loading={loading}
+        error={error}
+        emptyTitle="Keine Kunden gefunden"
+        emptyDescription="Passe Suche oder Filter an oder erstelle einen neuen Kunden."
+        onSort={handleSort}
+      />
+
+      <div className="flex items-center justify-between text-sm text-slate-600">
+        <span>Seite {currentPage} von {pageCount}</span>
+        <div className="flex gap-2">
+          <Button type="button" variant="outline" disabled={currentPage === 1} onClick={() => setPage((current) => Math.max(1, current - 1))}>Zurück</Button>
+          <Button type="button" variant="outline" disabled={currentPage === pageCount} onClick={() => setPage((current) => Math.min(pageCount, current + 1))}>Weiter</Button>
+        </div>
+      </div>
+
+      <CustomerFormDialog
+        open={formOpen}
+        customer={selectedCustomer}
+        pending={pending}
+        serverError={formError}
+        onOpenChange={setFormOpen}
+        onSubmit={saveCustomer}
+      />
+
+      <ConfirmDialog
+        open={Boolean(deleteCustomer)}
+        title="Kunde löschen"
+        description="Möchten Sie den Kunden wirklich löschen?"
+        pending={pending}
+        onOpenChange={(open) => {
+          if (!open) {
+            setDeleteCustomer(null);
+            setDeleteError("");
+          }
+        }}
+        onConfirm={confirmDelete}
+      >
+        {deleteCustomer && (
+          <dl className="grid gap-2 text-sm">
+            <div className="flex justify-between gap-4">
+              <dt className="text-slate-500">Kundennummer</dt>
+              <dd className="font-medium">{deleteCustomer.customer_number}</dd>
+            </div>
+            <div className="flex justify-between gap-4">
+              <dt className="text-slate-500">Firma</dt>
+              <dd className="font-medium">{deleteCustomer.company_name}</dd>
+            </div>
+            {deleteError && <p className="text-red-600">{deleteError}</p>}
+          </dl>
+        )}
+      </ConfirmDialog>
+    </div>
+  );
+}
--- a/frontend/athena/app/dashboard/page.tsx
+++ b/frontend/athena/app/dashboard/page.tsx
@ -1,15 +1,111 @@
-export default function DashboardPage() {
-    return (
-      <main className="min-h-screen bg-slate-100">
-        <div className="mx-auto max-w-7xl p-8">
-          <h1 className="text-4xl font-bold">
-            Olympus Dashboard
-          </h1>
+"use client";

-          <p className="mt-4 text-slate-600">
-            Willkommen bei Funktechnik Schubert.
-          </p>
+import { useCallback, useEffect, useState } from "react";
+import Link from "next/link";
+
+import SummaryCard from "@/components/common/SummaryCard";
+import { api } from "@/lib/api";
+import type { DashboardSummary, EmptyWidget } from "@/types/dashboard";
+
+function getErrorMessage(error: unknown) {
+  if (typeof error === "object" && error !== null && "response" in error) {
+    const response = (error as { response?: { data?: { detail?: string } } }).response;
+    return response?.data?.detail ?? "Dashboard konnte nicht geladen werden";
+  }
+  return "Dashboard konnte nicht geladen werden";
+}
+
+export default function DashboardPage() {
+  const [summary, setSummary] = useState<DashboardSummary | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState("");
+
+  const loadSummary = useCallback(async () => {
+    try {
+      const response = await api.get<DashboardSummary>("/dashboard/summary");
+      setSummary(response.data);
+    } catch (err) {
+      setError(getErrorMessage(err));
+    } finally {
+      setLoading(false);
+    }
+  }, []);
+
+  useEffect(() => {
+    queueMicrotask(() => {
+      void loadSummary();
+    });
+  }, [loadSummary]);
+
+  if (loading) {
+    return <div className="rounded-lg border bg-white p-8 text-slate-500">Dashboard wird geladen...</div>;
+  }
+
+  if (error || !summary) {
+    return <div className="rounded-lg border bg-white p-8 text-red-600">{error || "Keine Dashboarddaten verfügbar"}</div>;
+  }
+
+  const cards = [...summary.customers, ...summary.users, ...summary.roles];
+
+  return (
+    <div className="space-y-6">
+      <div>
+        <h1 className="text-3xl font-bold text-slate-950">Dashboard</h1>
+        <p className="mt-1 text-sm text-slate-500">Operative Übersicht für Olympus CRM</p>
+      </div>
+
+      {cards.length > 0 ? (
+        <div className="grid gap-4 md:grid-cols-2 xl:grid-cols-4">
+          {cards.map((card) => (
+            <SummaryCard key={card.label} label={card.label} value={card.value} />
+          ))}
+        </div>
+      ) : (
+        <EmptyPanel widget={{ title: "Keine Kennzahlen", message: "Für deine Berechtigungen sind aktuell keine Kennzahlen verfügbar." }} />
+      )}
+
+      <section className="rounded-lg border bg-white p-6">
+        <div className="mb-4 flex items-center justify-between">
+          <h2 className="text-lg font-semibold text-slate-950">Letzte Kunden</h2>
+          {summary.latest_customers.length > 0 && (
+            <Link href="/customers" className="text-sm font-medium text-slate-600 hover:text-slate-950">
+              Alle Kunden
+            </Link>
+          )}
+        </div>
+
+        {summary.latest_customers.length === 0 ? (
+          <p className="text-sm text-slate-500">Noch keine Kundendaten vorhanden.</p>
+        ) : (
+          <div className="divide-y">
+            {summary.latest_customers.map((customer) => (
+              <Link key={customer.id} href={`/customers/${customer.id}`} className="flex items-center justify-between py-3 hover:bg-slate-50">
+                <div>
+                  <p className="font-medium text-slate-950">{customer.company_name}</p>
+                  <p className="text-sm text-slate-500">{customer.customer_number}</p>
+                </div>
+                <span className="text-sm text-slate-500">{customer.status}</span>
+              </Link>
+            ))}
+          </div>
+        )}
+      </section>
+
+      <div className="grid gap-4 md:grid-cols-2 xl:grid-cols-4">
+        <EmptyPanel widget={summary.activities} />
+        <EmptyPanel widget={summary.tasks} />
+        <EmptyPanel widget={summary.tickets} />
+        <EmptyPanel widget={summary.projects} />
+      </div>
+    </div>
+  );
+}
+
+function EmptyPanel({ widget }: { widget: EmptyWidget }) {
+  return (
+    <div className="rounded-lg border bg-white p-5">
+      <h2 className="font-semibold text-slate-950">{widget.title}</h2>
+      <p className="mt-2 text-sm text-slate-500">{widget.message}</p>
    </div>
-      </main>
  );
 }
--- a/frontend/athena/components/Sidebar.tsx
+++ b/frontend/athena/components/Sidebar.tsx
@ -22,6 +22,7 @@ const menu = [
    icon: LayoutDashboard,
    name: "Dashboard",
    href: "/dashboard",
+    permission: "dashboard.read",
  },
  {
    icon: Users,
@ -39,6 +40,7 @@ const menu = [
    icon: Users,
    name: "Kunden",
    href: "/customers",
+    permission: "customers.read",
  },
  {
    icon: Wrench,
--- a/frontend/athena/components/common/DetailSection.tsx
+++ b/frontend/athena/components/common/DetailSection.tsx
@ -0,0 +1,19 @@
+import type { ReactNode } from "react";
+
+type Props = {
+  title: string;
+  actions?: ReactNode;
+  children: ReactNode;
+};
+
+export default function DetailSection({ title, actions, children }: Props) {
+  return (
+    <section className="rounded-lg border bg-white p-6">
+      <div className="mb-5 flex items-center justify-between gap-4">
+        <h2 className="text-lg font-semibold text-slate-950">{title}</h2>
+        {actions}
+      </div>
+      {children}
+    </section>
+  );
+}
--- a/frontend/athena/components/common/SummaryCard.tsx
+++ b/frontend/athena/components/common/SummaryCard.tsx
@ -0,0 +1,13 @@
+type Props = {
+  label: string;
+  value: number | string;
+};
+
+export default function SummaryCard({ label, value }: Props) {
+  return (
+    <div className="rounded-lg border bg-white p-5">
+      <p className="text-sm text-slate-500">{label}</p>
+      <p className="mt-2 text-3xl font-semibold text-slate-950">{value}</p>
+    </div>
+  );
+}
--- a/frontend/athena/components/customers/CustomerContactFormDialog.tsx
+++ b/frontend/athena/components/customers/CustomerContactFormDialog.tsx
@ -0,0 +1,188 @@
+"use client";
+
+import { useMemo, useState } from "react";
+import type { FormEvent, ReactNode } from "react";
+
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+} from "@/components/ui/dialog";
+import { Button } from "@/components/ui/button";
+import { Input } from "@/components/ui/input";
+import { Label } from "@/components/ui/label";
+import type { CustomerContact, CustomerContactPayload } from "@/types/customer";
+
+const emptyContact: CustomerContactPayload = {
+  first_name: "",
+  last_name: "",
+  position: "",
+  email: "",
+  phone: "",
+  mobile: "",
+  is_primary: false,
+  notes: "",
+};
+
+type Props = {
+  open: boolean;
+  contact?: CustomerContact | null;
+  pending?: boolean;
+  serverError?: string;
+  onOpenChange: (open: boolean) => void;
+  onSubmit: (payload: CustomerContactPayload) => Promise<void>;
+};
+
+export default function CustomerContactFormDialog({
+  open,
+  contact,
+  pending = false,
+  serverError,
+  onOpenChange,
+  onSubmit,
+}: Props) {
+  const initialForm = contact
+    ? {
+        first_name: contact.first_name,
+        last_name: contact.last_name,
+        position: contact.position,
+        email: contact.email,
+        phone: contact.phone,
+        mobile: contact.mobile,
+        is_primary: contact.is_primary,
+        notes: contact.notes,
+      }
+    : emptyContact;
+
+  return (
+    <Dialog open={open} onOpenChange={onOpenChange}>
+      <DialogContent className="sm:max-w-2xl">
+        {open && (
+          <ContactForm
+            key={contact?.id ?? "new"}
+            initialForm={initialForm}
+            pending={pending}
+            serverError={serverError}
+            onCancel={() => onOpenChange(false)}
+            onSubmit={onSubmit}
+          />
+        )}
+      </DialogContent>
+    </Dialog>
+  );
+}
+
+function ContactForm({
+  initialForm,
+  pending,
+  serverError,
+  onCancel,
+  onSubmit,
+}: {
+  initialForm: CustomerContactPayload;
+  pending: boolean;
+  serverError?: string;
+  onCancel: () => void;
+  onSubmit: (payload: CustomerContactPayload) => Promise<void>;
+}) {
+  const [form, setForm] = useState<CustomerContactPayload>(initialForm);
+  const errors = useMemo(() => ({
+    name: form.first_name.trim() || form.last_name.trim()
+      ? ""
+      : "Vorname oder Nachname erforderlich",
+    email: !form.email || /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(form.email)
+      ? ""
+      : "Gültige E-Mail erforderlich",
+  }), [form.email, form.first_name, form.last_name]);
+  const valid = Object.values(errors).every((error) => !error);
+
+  function update<K extends keyof CustomerContactPayload>(key: K, value: CustomerContactPayload[K]) {
+    setForm((current) => ({ ...current, [key]: value }));
+  }
+
+  async function handleSubmit(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault();
+    if (!valid) {
+      return;
+    }
+
+    await onSubmit({
+      ...form,
+      email: form.email?.trim() || null,
+    });
+  }
+
+  return (
+    <form onSubmit={handleSubmit} className="space-y-5">
+      <DialogHeader>
+        <DialogTitle>Ansprechpartner {initialForm.first_name || initialForm.last_name ? "bearbeiten" : "hinzufügen"}</DialogTitle>
+        <DialogDescription>Ansprechpartnerdaten und Primärkennzeichnung pflegen.</DialogDescription>
+      </DialogHeader>
+
+      <div className="grid gap-4 sm:grid-cols-2">
+        <Field label="Vorname" error={errors.name}>
+          <Input value={form.first_name} onChange={(event) => update("first_name", event.target.value)} />
+        </Field>
+        <Field label="Nachname">
+          <Input value={form.last_name} onChange={(event) => update("last_name", event.target.value)} />
+        </Field>
+        <Field label="Position">
+          <Input value={form.position} onChange={(event) => update("position", event.target.value)} />
+        </Field>
+        <Field label="E-Mail" error={errors.email}>
+          <Input type="email" value={form.email ?? ""} onChange={(event) => update("email", event.target.value)} />
+        </Field>
+        <Field label="Telefon">
+          <Input value={form.phone} onChange={(event) => update("phone", event.target.value)} />
+        </Field>
+        <Field label="Mobil">
+          <Input value={form.mobile} onChange={(event) => update("mobile", event.target.value)} />
+        </Field>
+        <label className="flex h-8 items-center gap-2 rounded-lg border px-2.5 text-sm">
+          <input
+            type="checkbox"
+            checked={form.is_primary}
+            onChange={(event) => update("is_primary", event.target.checked)}
+          />
+          Primärer Ansprechpartner
+        </label>
+      </div>
+
+      <Field label="Notizen">
+        <Input value={form.notes} onChange={(event) => update("notes", event.target.value)} />
+      </Field>
+
+      {serverError && <p className="text-sm text-red-600">{serverError}</p>}
+
+      <DialogFooter>
+        <Button type="button" variant="outline" disabled={pending} onClick={onCancel}>
+          Abbrechen
+        </Button>
+        <Button type="submit" disabled={!valid || pending}>
+          {pending ? "Speichern..." : "Speichern"}
+        </Button>
+      </DialogFooter>
+    </form>
+  );
+}
+
+function Field({
+  label,
+  error,
+  children,
+}: {
+  label: string;
+  error?: string;
+  children: ReactNode;
+}) {
+  return (
+    <div className="space-y-1.5">
+      <Label>{label}</Label>
+      {children}
+      {error && <p className="text-xs text-red-600">{error}</p>}
+    </div>
+  );
+}
--- a/frontend/athena/components/customers/CustomerFormDialog.tsx
+++ b/frontend/athena/components/customers/CustomerFormDialog.tsx
@ -0,0 +1,283 @@
+"use client";
+
+import { useMemo, useState } from "react";
+import type { FormEvent } from "react";
+
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+} from "@/components/ui/dialog";
+import { Button } from "@/components/ui/button";
+import { Input } from "@/components/ui/input";
+import { Label } from "@/components/ui/label";
+import type { Customer, CustomerPayload, CustomerStatus, CustomerType } from "@/types/customer";
+
+const customerTypes: Array<{ value: CustomerType; label: string }> = [
+  { value: "company", label: "Unternehmen" },
+  { value: "private", label: "Privat" },
+  { value: "public_sector", label: "Öffentlicher Sektor" },
+  { value: "partner", label: "Partner" },
+  { value: "supplier", label: "Lieferant" },
+];
+
+const statuses: Array<{ value: CustomerStatus; label: string }> = [
+  { value: "lead", label: "Lead" },
+  { value: "active", label: "Aktiv" },
+  { value: "inactive", label: "Inaktiv" },
+  { value: "blocked", label: "Gesperrt" },
+  { value: "archived", label: "Archiviert" },
+];
+
+const emptyCustomer: CustomerPayload = {
+  customer_number: "",
+  company_name: "",
+  legal_name: "",
+  customer_type: "company",
+  status: "lead",
+  industry: "",
+  website: "",
+  email: "",
+  phone: "",
+  tax_number: "",
+  vat_id: "",
+  notes: "",
+  addresses: [
+    {
+      type: "primary",
+      street: "",
+      postal_code: "",
+      city: "",
+      state: "",
+      country: "Deutschland",
+      is_primary: true,
+    },
+  ],
+};
+
+type Props = {
+  open: boolean;
+  customer?: Customer | null;
+  pending?: boolean;
+  serverError?: string;
+  onOpenChange: (open: boolean) => void;
+  onSubmit: (payload: CustomerPayload) => Promise<void>;
+};
+
+export default function CustomerFormDialog({
+  open,
+  customer,
+  pending = false,
+  serverError,
+  onOpenChange,
+  onSubmit,
+}: Props) {
+  const initialForm = customer
+    ? {
+        customer_number: customer.customer_number,
+        company_name: customer.company_name,
+        legal_name: customer.legal_name,
+        customer_type: customer.customer_type,
+        status: customer.status,
+        industry: customer.industry,
+        website: customer.website,
+        email: customer.email,
+        phone: customer.phone,
+        tax_number: customer.tax_number,
+        vat_id: customer.vat_id,
+        notes: customer.notes,
+        addresses: customer.addresses.length > 0
+          ? customer.addresses.map((address) => ({
+              type: address.type,
+              street: address.street,
+              postal_code: address.postal_code,
+              city: address.city,
+              state: address.state,
+              country: address.country,
+              is_primary: address.is_primary,
+            }))
+          : emptyCustomer.addresses,
+      }
+    : emptyCustomer;
+
+  return (
+    <Dialog open={open} onOpenChange={onOpenChange}>
+      <DialogContent className="sm:max-w-3xl">
+        {open && (
+          <CustomerForm
+            key={customer?.id ?? "new"}
+            initialForm={initialForm}
+            pending={pending}
+            serverError={serverError}
+            onCancel={() => onOpenChange(false)}
+            onSubmit={onSubmit}
+          />
+        )}
+      </DialogContent>
+    </Dialog>
+  );
+}
+
+function CustomerForm({
+  initialForm,
+  pending,
+  serverError,
+  onCancel,
+  onSubmit,
+}: {
+  initialForm: CustomerPayload;
+  pending: boolean;
+  serverError?: string;
+  onCancel: () => void;
+  onSubmit: (payload: CustomerPayload) => Promise<void>;
+}) {
+  const [form, setForm] = useState<CustomerPayload>(initialForm);
+
+  const errors = useMemo(() => ({
+    customer_number: form.customer_number.trim() ? "" : "Kundennummer erforderlich",
+    company_name: form.company_name.trim() ? "" : "Firmenname erforderlich",
+    email: !form.email || /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(form.email)
+      ? ""
+      : "Gültige E-Mail erforderlich",
+  }), [form.company_name, form.customer_number, form.email]);
+
+  const valid = Object.values(errors).every((error) => !error);
+
+  function update<K extends keyof CustomerPayload>(key: K, value: CustomerPayload[K]) {
+    setForm((current) => ({ ...current, [key]: value }));
+  }
+
+  function updateAddress(index: number, key: keyof CustomerPayload["addresses"][number], value: string | boolean) {
+    setForm((current) => ({
+      ...current,
+      addresses: current.addresses.map((address, itemIndex) => (
+        itemIndex === index
+          ? { ...address, [key]: value }
+          : key === "is_primary" && value === true
+            ? { ...address, is_primary: false }
+            : address
+      )),
+    }));
+  }
+
+  async function handleSubmit(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault();
+    if (!valid) {
+      return;
+    }
+
+    await onSubmit({
+      ...form,
+      website: form.website?.trim() || null,
+      email: form.email?.trim() || null,
+      addresses: form.addresses.map((address, index) => ({
+        ...address,
+        is_primary: address.is_primary || index === 0,
+      })),
+    });
+  }
+
+  return (
+    <form onSubmit={handleSubmit} className="space-y-5">
+      <DialogHeader>
+        <DialogTitle>Kunde {initialForm.customer_number ? "bearbeiten" : "erstellen"}</DialogTitle>
+        <DialogDescription>
+          Stammdaten und primäre Adresse des Kunden verwalten.
+        </DialogDescription>
+      </DialogHeader>
+
+      <div className="grid gap-4 sm:grid-cols-2">
+        <Field label="Kundennummer" error={errors.customer_number}>
+          <Input value={form.customer_number} onChange={(event) => update("customer_number", event.target.value)} />
+        </Field>
+        <Field label="Firmenname" error={errors.company_name}>
+          <Input value={form.company_name} onChange={(event) => update("company_name", event.target.value)} />
+        </Field>
+        <Field label="Rechtlicher Name">
+          <Input value={form.legal_name} onChange={(event) => update("legal_name", event.target.value)} />
+        </Field>
+        <Field label="Branche">
+          <Input value={form.industry} onChange={(event) => update("industry", event.target.value)} />
+        </Field>
+        <Field label="Typ">
+          <select value={form.customer_type} onChange={(event) => update("customer_type", event.target.value as CustomerType)} className="h-8 w-full rounded-lg border border-input bg-transparent px-2.5 text-sm">
+            {customerTypes.map((type) => <option key={type.value} value={type.value}>{type.label}</option>)}
+          </select>
+        </Field>
+        <Field label="Status">
+          <select value={form.status} onChange={(event) => update("status", event.target.value as CustomerStatus)} className="h-8 w-full rounded-lg border border-input bg-transparent px-2.5 text-sm">
+            {statuses.map((status) => <option key={status.value} value={status.value}>{status.label}</option>)}
+          </select>
+        </Field>
+        <Field label="E-Mail" error={errors.email}>
+          <Input type="email" value={form.email ?? ""} onChange={(event) => update("email", event.target.value)} />
+        </Field>
+        <Field label="Telefon">
+          <Input value={form.phone} onChange={(event) => update("phone", event.target.value)} />
+        </Field>
+        <Field label="Website">
+          <Input value={form.website ?? ""} onChange={(event) => update("website", event.target.value)} />
+        </Field>
+        <Field label="USt-ID">
+          <Input value={form.vat_id} onChange={(event) => update("vat_id", event.target.value)} />
+        </Field>
+      </div>
+
+      <div className="rounded-lg border p-4">
+        <h3 className="mb-4 text-sm font-semibold">Primäradresse</h3>
+        {form.addresses.slice(0, 1).map((address, index) => (
+          <div key={index} className="grid gap-4 sm:grid-cols-2">
+            <Field label="Straße">
+              <Input value={address.street} onChange={(event) => updateAddress(index, "street", event.target.value)} />
+            </Field>
+            <Field label="PLZ">
+              <Input value={address.postal_code} onChange={(event) => updateAddress(index, "postal_code", event.target.value)} />
+            </Field>
+            <Field label="Ort">
+              <Input value={address.city} onChange={(event) => updateAddress(index, "city", event.target.value)} />
+            </Field>
+            <Field label="Land">
+              <Input value={address.country} onChange={(event) => updateAddress(index, "country", event.target.value)} />
+            </Field>
+          </div>
+        ))}
+      </div>
+
+      <Field label="Notizen">
+        <Input value={form.notes} onChange={(event) => update("notes", event.target.value)} />
+      </Field>
+
+      {serverError && <p className="text-sm text-red-600">{serverError}</p>}
+
+      <DialogFooter>
+        <Button type="button" variant="outline" disabled={pending} onClick={onCancel}>
+          Abbrechen
+        </Button>
+        <Button type="submit" disabled={!valid || pending}>
+          {pending ? "Speichern..." : "Speichern"}
+        </Button>
+      </DialogFooter>
+    </form>
+  );
+}
+
+function Field({
+  label,
+  error,
+  children,
+}: {
+  label: string;
+  error?: string;
+  children: React.ReactNode;
+}) {
+  return (
+    <div className="space-y-1.5">
+      <Label>{label}</Label>
+      {children}
+      {error && <p className="text-xs text-red-600">{error}</p>}
+    </div>
+  );
+}
--- a/frontend/athena/components/customers/CustomerStatusBadge.tsx
+++ b/frontend/athena/components/customers/CustomerStatusBadge.tsx
@ -0,0 +1,26 @@
+import { cn } from "@/lib/utils";
+import type { CustomerStatus } from "@/types/customer";
+
+const labels: Record<CustomerStatus, string> = {
+  lead: "Lead",
+  active: "Aktiv",
+  inactive: "Inaktiv",
+  blocked: "Gesperrt",
+  archived: "Archiviert",
+};
+
+const styles: Record<CustomerStatus, string> = {
+  lead: "bg-sky-50 text-sky-700 ring-sky-600/20",
+  active: "bg-emerald-50 text-emerald-700 ring-emerald-600/20",
+  inactive: "bg-slate-100 text-slate-600 ring-slate-500/20",
+  blocked: "bg-red-50 text-red-700 ring-red-600/20",
+  archived: "bg-zinc-100 text-zinc-600 ring-zinc-500/20",
+};
+
+export default function CustomerStatusBadge({ status }: { status: CustomerStatus }) {
+  return (
+    <span className={cn("inline-flex h-6 items-center rounded-full px-2 text-xs font-medium ring-1", styles[status])}>
+      {labels[status]}
+    </span>
+  );
+}
--- a/frontend/athena/proxy.ts
+++ b/frontend/athena/proxy.ts
@ -21,5 +21,6 @@ export const config = {
    "/dashboard/:path*",
    "/users/:path*",
    "/roles/:path*",
+    "/customers/:path*",
  ],
 };
--- a/frontend/athena/types/customer.ts
+++ b/frontend/athena/types/customer.ts
@ -0,0 +1,89 @@
+export type CustomerStatus = "lead" | "active" | "inactive" | "blocked" | "archived";
+export type CustomerType = "company" | "private" | "public_sector" | "partner" | "supplier";
+export type AddressType = "billing" | "shipping" | "primary" | "other";
+
+export interface CustomerAddress {
+  id: number;
+  customer_id: number;
+  type: AddressType;
+  street: string;
+  postal_code: string;
+  city: string;
+  state: string;
+  country: string;
+  is_primary: boolean;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface CustomerContact {
+  id: number;
+  customer_id: number;
+  first_name: string;
+  last_name: string;
+  position: string;
+  email: string;
+  phone: string;
+  mobile: string;
+  is_primary: boolean;
+  notes: string;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface Customer {
+  id: number;
+  customer_number: string;
+  company_name: string;
+  legal_name: string;
+  customer_type: CustomerType;
+  status: CustomerStatus;
+  industry: string;
+  website: string;
+  email: string;
+  phone: string;
+  tax_number: string;
+  vat_id: string;
+  notes: string;
+  addresses: CustomerAddress[];
+  contacts: CustomerContact[];
+  created_at: string;
+  updated_at: string;
+}
+
+export type CustomerPayload = {
+  customer_number: string;
+  company_name: string;
+  legal_name: string;
+  customer_type: CustomerType;
+  status: CustomerStatus;
+  industry: string;
+  website?: string | null;
+  email?: string | null;
+  phone: string;
+  tax_number: string;
+  vat_id: string;
+  notes: string;
+  addresses: CustomerAddressPayload[];
+};
+
+export type CustomerAddressPayload = {
+  type: AddressType;
+  street: string;
+  postal_code: string;
+  city: string;
+  state: string;
+  country: string;
+  is_primary: boolean;
+};
+
+export type CustomerContactPayload = {
+  first_name: string;
+  last_name: string;
+  position: string;
+  email?: string | null;
+  phone: string;
+  mobile: string;
+  is_primary: boolean;
+  notes: string;
+};
--- a/frontend/athena/types/dashboard.ts
+++ b/frontend/athena/types/dashboard.ts
@ -0,0 +1,22 @@
+import type { Customer } from "@/types/customer";
+
+export interface MetricCard {
+  label: string;
+  value: number;
+}
+
+export interface EmptyWidget {
+  title: string;
+  message: string;
+}
+
+export interface DashboardSummary {
+  customers: MetricCard[];
+  latest_customers: Customer[];
+  users: MetricCard[];
+  roles: MetricCard[];
+  activities: EmptyWidget;
+  tasks: EmptyWidget;
+  tickets: EmptyWidget;
+  projects: EmptyWidget;
+}