diff --git a/app/api/routers/projects.py b/app/api/routers/projects.py
index 9c97843..30c2c08 100644
--- a/app/api/routers/projects.py
+++ b/app/api/routers/projects.py
@@ -15,6 +15,19 @@ from app.api.rbac import check_project_role, check_permission, ensure_can_edit_p
 router = APIRouter(prefix="/projects", tags=["Projects"])
 
 
+def _resolve_project(db: Session, identifier: str) -> models.Project:
+    """Resolve a project by numeric id or project_code string.
+    Raises 404 if not found."""
+    try:
+        pid = int(identifier)
+        project = db.query(models.Project).filter(models.Project.id == pid).first()
+    except (ValueError, TypeError):
+        project = db.query(models.Project).filter(models.Project.project_code == identifier).first()
+    if not project:
+        raise HTTPException(status_code=404, detail="Project not found")
+    return _resolve_project(db, project_id)
+
+
 def _validate_project_links(db, codes: list[str] | None, self_code: str | None = None) -> list[str] | None:
     if not codes:
         return None
@@ -183,16 +196,13 @@ def list_projects(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)
 
 
 @router.get("/{project_id}", response_model=schemas.ProjectResponse)
-def get_project(project_id: int, db: Session = Depends(get_db)):
-    project = db.query(models.Project).filter(models.Project.id == project_id).first()
-    if not project:
-        raise HTTPException(status_code=404, detail="Project not found")
-    return project
+def get_project(project_id: str, db: Session = Depends(get_db)):
+    return _resolve_project(db, project_id)
 
 
 @router.patch("/{project_id}", response_model=schemas.ProjectResponse)
 def update_project(
-    project_id: int,
+    project_id: str,
     project_update: schemas.ProjectUpdate,
     db: Session = Depends(get_db),
     current_user: models.User = Depends(get_current_user_or_apikey),
@@ -215,26 +225,25 @@ def update_project(
         setattr(project, field, value)
     db.commit()
     db.refresh(project)
-    return project
+    return _resolve_project(db, project_id)
 
 
 @router.delete("/{project_id}", status_code=status.HTTP_204_NO_CONTENT)
 def delete_project(
-    project_id: int,
+    project_id: str,
     db: Session = Depends(get_db),
     current_user: models.User = Depends(get_current_user_or_apikey),
 ):
-    check_project_role(db, current_user.id, project_id, min_role="admin")
-    project = db.query(models.Project).filter(models.Project.id == project_id).first()
-    if not project:
-        raise HTTPException(status_code=404, detail="Project not found")
+    project = _resolve_project(db, project_id)
+    check_project_role(db, current_user.id, project.id, min_role="admin")
     
     project_code = project.project_code
+    project_id_val = project.id
     
     # Delete milestones and their tasks
     from app.models.milestone import Milestone
     from app.models.task import Task
-    milestones = db.query(Milestone).filter(Milestone.project_id == project_id).all()
+    milestones = db.query(Milestone).filter(Milestone.project_id == project_id_val).all()
     for ms in milestones:
         tasks = db.query(Task).filter(Task.milestone_id == ms.id).all()
         for task in tasks:
@@ -242,7 +251,7 @@ def delete_project(
         db.delete(ms)
     
     # Delete project members
-    members = db.query(models.ProjectMember).filter(models.ProjectMember.project_id == project_id).all()
+    members = db.query(models.ProjectMember).filter(models.ProjectMember.project_id == project.id).all()
     for m in members:
         db.delete(m)
     
@@ -269,27 +278,25 @@ def delete_project(
 
 @router.post("/{project_id}/members", response_model=schemas.ProjectMemberResponse, status_code=status.HTTP_201_CREATED)
 def add_project_member(
-    project_id: int,
+    project_id: str,
     member: schemas.ProjectMemberCreate,
     db: Session = Depends(get_db),
     current_user: models.User = Depends(get_current_user_or_apikey),
 ):
-    check_project_role(db, current_user.id, project_id, min_role="mgr")
-    project = db.query(models.Project).filter(models.Project.id == project_id).first()
-    if not project:
-        raise HTTPException(status_code=404, detail="Project not found")
+    project = _resolve_project(db, project_id)
+    check_project_role(db, current_user.id, project.id, min_role="mgr")
     user = db.query(models.User).filter(models.User.id == member.user_id).first()
     if not user:
         raise HTTPException(status_code=404, detail="User not found")
     existing = db.query(models.ProjectMember).filter(
-        models.ProjectMember.project_id == project_id, models.ProjectMember.user_id == member.user_id
+        models.ProjectMember.project_id == project.id, models.ProjectMember.user_id == member.user_id
     ).first()
     if existing:
         raise HTTPException(status_code=400, detail="User already a member")
     # Convert role name to role_id
     role = db.query(Role).filter(Role.name == member.role).first()
     role_id = role.id if role else None
-    db_member = models.ProjectMember(project_id=project_id, user_id=member.user_id, role_id=role_id)
+    db_member = models.ProjectMember(project_id=project.id, user_id=member.user_id, role_id=role_id)
     db.add(db_member)
     db.commit()
     db.refresh(db_member)
@@ -308,7 +315,7 @@ def add_project_member(
 
 @router.get("/{project_id}/members", response_model=List[schemas.ProjectMemberResponse])
 def list_project_members(project_id: int, db: Session = Depends(get_db)):
-    members = db.query(models.ProjectMember).filter(models.ProjectMember.project_id == project_id).all()
+    members = db.query(models.ProjectMember).filter(models.ProjectMember.project_id == project.id).all()
     result = []
     for m in members:
         role_name = "developer"
@@ -327,7 +334,7 @@ def list_project_members(project_id: int, db: Session = Depends(get_db)):
 
 @router.delete("/{project_id}/members/{user_id}", status_code=status.HTTP_204_NO_CONTENT)
 def remove_project_member(
-    project_id: int,
+    project_id: str,
     user_id: int,
     db: Session = Depends(get_db),
     current_user: models.User = Depends(get_current_user_or_apikey),