diff --git a/backend/src/backend/__pycache__/main.cpython-314.pyc b/backend/src/backend/__pycache__/main.cpython-314.pyc
index 1f02bd3..a322364 100644
Binary files a/backend/src/backend/__pycache__/main.cpython-314.pyc and b/backend/src/backend/__pycache__/main.cpython-314.pyc differ
diff --git a/backend/src/backend/internal/__pycache__/user_code_gen.cpython-314.pyc b/backend/src/backend/internal/__pycache__/user_code_gen.cpython-314.pyc
new file mode 100644
index 0000000..7a5dca9
Binary files /dev/null and b/backend/src/backend/internal/__pycache__/user_code_gen.cpython-314.pyc differ
diff --git a/backend/src/backend/internal/user_code_gen.py b/backend/src/backend/internal/user_code_gen.py
new file mode 100644
index 0000000..bf82c3d
--- /dev/null
+++ b/backend/src/backend/internal/user_code_gen.py
@@ -0,0 +1,4 @@
+import string
+import random
+def generate_user_code() -> str:
+    return ''.join(random.choices(string.ascii_letters, k=4)).upper()
diff --git a/backend/src/backend/main.py b/backend/src/backend/main.py
index e9892ce..9a5062d 100644
--- a/backend/src/backend/main.py
+++ b/backend/src/backend/main.py
@@ -17,6 +17,4 @@ def on_startup():
 router = APIRouter()
 
 app.include_router(users.router)
-app.include_router(comments.router)
-
-print(SQLModel.metadata.tables.keys())
+app.include_router(comments.router)
\ No newline at end of file
diff --git a/backend/src/backend/models/__pycache__/user.cpython-314.pyc b/backend/src/backend/models/__pycache__/user.cpython-314.pyc
index 69ea8e6..1475983 100644
Binary files a/backend/src/backend/models/__pycache__/user.cpython-314.pyc and b/backend/src/backend/models/__pycache__/user.cpython-314.pyc differ
diff --git a/backend/src/backend/models/user.py b/backend/src/backend/models/user.py
index 90923aa..844b898 100644
--- a/backend/src/backend/models/user.py
+++ b/backend/src/backend/models/user.py
@@ -1,3 +1,5 @@
+from backend.internal.user_code_gen import generate_user_code
+from dataclasses import dataclass
 import uuid
 from typing import TYPE_CHECKING
 from sqlmodel import Field
@@ -14,10 +16,11 @@ class User(UserBase, table=True):
     id: uuid.UUID = Field(default_factory=uuid.uuid4, primary_key=True)
     email: str = Field(unique=True)
     name: str = Field(unique=True)
-    user_code: str = Field(default="1234",unique=True) # TODO: create Generator
+    user_code: str = Field(default_factory=generate_user_code,unique=True)
     subscription: bool = Field()
     comments: list["Comment"] = Relationship(back_populates="user")
 
+@dataclass
 class NewUser(UserBase):
     email: str
     name: str
diff --git a/backend/src/backend/routers/__pycache__/test_users.cpython-314-pytest-9.1.1.pyc b/backend/src/backend/routers/__pycache__/test_users.cpython-314-pytest-9.1.1.pyc
index a17eab1..7997263 100644
Binary files a/backend/src/backend/routers/__pycache__/test_users.cpython-314-pytest-9.1.1.pyc and b/backend/src/backend/routers/__pycache__/test_users.cpython-314-pytest-9.1.1.pyc differ
diff --git a/backend/src/backend/routers/test_users.py b/backend/src/backend/routers/test_users.py
index ff62a1c..78e2219 100644
--- a/backend/src/backend/routers/test_users.py
+++ b/backend/src/backend/routers/test_users.py
@@ -1,3 +1,5 @@
+from backend.models.user import NewUser
+from sqlmodel import select
 from backend.models.user import User
 from backend.internal.database import get_session
 from sqlmodel import Session
@@ -30,11 +32,7 @@ def client_fixture(session: Session):
     yield client  
     app.dependency_overrides.clear()  
 
-
-
-
-def test_register_user_works(client: TestClient):
-    print(SQLModel.metadata.tables.keys())
+def test_register_user_saved(session:Session, client: TestClient):
     new_user = {
         "email": "Test@Test.test",
         "name": "Test1",
@@ -43,15 +41,26 @@ def test_register_user_works(client: TestClient):
     response = client.post(url="/users/", json=new_user)
     assert response.status_code == 200
 
-def test_email_not_unique(session: Session, client: TestClient):
-    new_user = {
-        "email": "Test@Test.test",
-        "name": "Test1",
-        "subscription": True
-    }
-    user = User.model_validate(new_user)
+    db_user = session.exec(select(User).where(User.email == "Test@Test.test")).first()
+    assert db_user
+    assert db_user.email == "Test@Test.test"
+    assert db_user.name == "Test1"
+    assert db_user.subscription == True
+
+def test_email_not_unique_returns_400(session: Session, client: TestClient):
+    new_user = NewUser(email="Not@Unique.de",name="Tim", subscription=True)
+
+    user = User.model_validate(new_user.model_copy(update={'name':'Different'}))
     session.add(user)
     session.commit()
-    response = client.post(url="/users/", json=new_user)
-    
+    response = client.post(url="/users/", json=new_user.model_dump())
+    assert response.status_code == 400
+
+def test_name_not_unique_returns_400(session: Session, client: TestClient):
+    new_user = NewUser(email="Absolutly@Unique.de",name="Chiara", subscription=True)
+
+    user = User.model_validate(new_user.model_copy(update={'email':'Different@Different.de'}))
+    session.add(user)
+    session.commit()
+    response = client.post(url="/users/", json=new_user.model_dump())
     assert response.status_code == 400
\ No newline at end of file