diff --git a/app/backend/models/user.py b/app/backend/models/user.py
index baf1635c3c8a51898dda92f042454bb213d01a06..34945afd753e38f90729effb754ee19da741e74a 100644
--- a/app/backend/models/user.py
+++ b/app/backend/models/user.py
@@ -4,7 +4,8 @@ from typing import Optional
 
 class User(SQLModel, table=True):
     id: Optional[int] = Field(default=None, primary_key=True)
-    username: str = Field(unique=True, index=True)
+    username: str
     email: str = Field(unique=True, index=True)
+    phone_number: str
     password: str
     role: str  # "buyer" or "shop_owner"
diff --git a/app/backend/routes/auth.py b/app/backend/routes/auth.py
index e208d7db7d89fca5bf9d844cb70bd0acb938a8c8..2d835ce683e5f35038bd2a692ccb9ca58efe9667 100644
--- a/app/backend/routes/auth.py
+++ b/app/backend/routes/auth.py
@@ -21,6 +21,7 @@ def signup(user_data: UserCreate, session: Session = Depends(get_session)):
         username=user_data.username,
         email=user_data.email,
         password=hashed_password,
+        phone_number=user_data.phone_number,
         role="buyer",
     )
     session.add(user)
diff --git a/app/backend/schemas/user.py b/app/backend/schemas/user.py
index 74f76314498ac1719607dc40b22d437a3cb83f23..9328e1b17529f6285a5bc83743d19197b1d8c801 100644
--- a/app/backend/schemas/user.py
+++ b/app/backend/schemas/user.py
@@ -6,6 +6,7 @@ from typing import Optional
 class UserCreate(BaseModel):
     username: str
     email: EmailStr
+    phone_number: str
     password: str