diff --git a/app/api/v1/deals/models.py b/app/api/v1/deals/models.py
index 3ebb08e..620320f 100644
--- a/app/api/v1/deals/models.py
+++ b/app/api/v1/deals/models.py
@@ -5,16 +5,29 @@ from decimal import Decimal
 
 from pydantic import BaseModel
 
+from app.models.deal import DealCreate, DealStage, DealStatus
+
 
 class DealCreatePayload(BaseModel):
     contact_id: int
     title: str
     amount: Decimal | None = None
     currency: str | None = None
+    owner_id: int | None = None
+
+    def to_domain(self, *, organization_id: int, fallback_owner: int) -> DealCreate:
+        return DealCreate(
+            organization_id=organization_id,
+            contact_id=self.contact_id,
+            owner_id=self.owner_id or fallback_owner,
+            title=self.title,
+            amount=self.amount,
+            currency=self.currency,
+        )
 
 
 class DealUpdatePayload(BaseModel):
-    status: str | None = None
-    stage: str | None = None
+    status: DealStatus | None = None
+    stage: DealStage | None = None
     amount: Decimal | None = None
     currency: str | None = None
diff --git a/app/api/v1/deals/views.py b/app/api/v1/deals/views.py
index e10b22d..937b97b 100644
--- a/app/api/v1/deals/views.py
+++ b/app/api/v1/deals/views.py
@@ -1,11 +1,19 @@
-"""Deal API stubs covering list/create/update operations."""
+"""Deal API endpoints backed by DealService."""
 from __future__ import annotations
 
 from decimal import Decimal
 
-from fastapi import APIRouter, Depends, Query, status
+from fastapi import APIRouter, Depends, HTTPException, Query, status
 
-from app.api.deps import get_organization_context
+from app.api.deps import get_deal_repository, get_deal_service, get_organization_context
+from app.models.deal import DealRead, DealStage, DealStatus
+from app.repositories.deal_repo import DealRepository, DealAccessError, DealQueryParams
+from app.services.deal_service import (
+    DealService,
+    DealStageTransitionError,
+    DealStatusValidationError,
+    DealUpdateData,
+)
 from app.services.organization_service import OrganizationContext
 
 from .models import DealCreatePayload, DealUpdatePayload
@@ -13,11 +21,7 @@ from .models import DealCreatePayload, DealUpdatePayload
 router = APIRouter(prefix="/deals", tags=["deals"])
 
 
-def _stub(endpoint: str) -> dict[str, str]:
-    return {"detail": f"{endpoint} is not implemented yet"}
-
-
-@router.get("/", status_code=status.HTTP_501_NOT_IMPLEMENTED)
+@router.get("/", response_model=list[DealRead])
 async def list_deals(
     page: int = Query(1, ge=1),
     page_size: int = Query(20, ge=1, le=100),
@@ -27,30 +31,90 @@ async def list_deals(
     stage: str | None = None,
     owner_id: int | None = None,
     order_by: str | None = None,
-    order: str | None = Query(default=None, pattern="^(asc|desc)$"),
+    order: str | None = Query(default="desc", pattern="^(asc|desc)$"),
     context: OrganizationContext = Depends(get_organization_context),
-) -> dict[str, str]:
-    """Placeholder for deal filtering endpoint."""
-    _ = (status_filter, context)
-    return _stub("GET /deals")
+    repo: DealRepository = Depends(get_deal_repository),
+) -> list[DealRead]:
+    """List deals for the current organization with optional filters."""
+
+    try:
+        statuses_value = [DealStatus(value) for value in status_filter] if status_filter else None
+        stage_value = DealStage(stage) if stage else None
+    except ValueError as exc:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Invalid deal filter") from exc
+
+    params = DealQueryParams(
+        organization_id=context.organization_id,
+        page=page,
+        page_size=page_size,
+        statuses=statuses_value,
+        stage=stage_value,
+        owner_id=owner_id,
+        min_amount=min_amount,
+        max_amount=max_amount,
+        order_by=order_by,
+        order_desc=(order != "asc"),
+    )
+    try:
+        deals = await repo.list(params=params, role=context.role, user_id=context.user_id)
+    except DealAccessError as exc:
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail=str(exc)) from exc
+
+    return [DealRead.model_validate(deal) for deal in deals]
 
 
-@router.post("/", status_code=status.HTTP_501_NOT_IMPLEMENTED)
+@router.post("/", response_model=DealRead, status_code=status.HTTP_201_CREATED)
 async def create_deal(
     payload: DealCreatePayload,
     context: OrganizationContext = Depends(get_organization_context),
-) -> dict[str, str]:
-    """Placeholder for creating a new deal."""
-    _ = (payload, context)
-    return _stub("POST /deals")
+    service: DealService = Depends(get_deal_service),
+) -> DealRead:
+    """Create a new deal within the current organization."""
+
+    data = payload.to_domain(organization_id=context.organization_id, fallback_owner=context.user_id)
+    try:
+        deal = await service.create_deal(data, context=context)
+    except DealAccessError as exc:
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail=str(exc)) from exc
+    except DealStatusValidationError as exc:  # pragma: no cover - creation shouldn't trigger
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
+
+    return DealRead.model_validate(deal)
 
 
-@router.patch("/{deal_id}", status_code=status.HTTP_501_NOT_IMPLEMENTED)
+@router.patch("/{deal_id}", response_model=DealRead)
 async def update_deal(
     deal_id: int,
     payload: DealUpdatePayload,
     context: OrganizationContext = Depends(get_organization_context),
-) -> dict[str, str]:
-    """Placeholder for modifying deal status or stage."""
-    _ = (deal_id, payload, context)
-    return _stub("PATCH /deals/{deal_id}")
+    repo: DealRepository = Depends(get_deal_repository),
+    service: DealService = Depends(get_deal_service),
+) -> DealRead:
+    """Update deal status, stage, or financial data."""
+
+    existing = await repo.get(
+        deal_id,
+        organization_id=context.organization_id,
+        role=context.role,
+        user_id=context.user_id,
+    )
+    if existing is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Deal not found")
+
+    updates = DealUpdateData(
+        status=payload.status,
+        stage=payload.stage,
+        amount=payload.amount,
+        currency=payload.currency,
+    )
+
+    try:
+        deal = await service.update_deal(existing, updates, context=context)
+    except DealAccessError as exc:
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail=str(exc)) from exc
+    except DealStageTransitionError as exc:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
+    except DealStatusValidationError as exc:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
+
+    return DealRead.model_validate(deal)
diff --git a/app/services/__init__.py b/app/services/__init__.py
index 3e15215..e235f99 100644
--- a/app/services/__init__.py
+++ b/app/services/__init__.py
@@ -1,6 +1,4 @@
 """Business logic services."""
-
-from .deal_service import DealService  # noqa: F401
 from .organization_service import (  # noqa: F401
     OrganizationAccessDeniedError,
     OrganizationContext,