diff --git a/.git-blame-ignore-revs b/.git-blame-ignore-revs
index 2ee1cc3..36f331f 100644
--- a/.git-blame-ignore-revs
+++ b/.git-blame-ignore-revs
@@ -1,2 +1,3 @@
 # Migrate code style to Black
 41e60425a96eeddb45f3a9f9bfc5ef491ce8e071
+36c4027c5dd1c631bf6ca84890b6ad9c916e1888
diff --git a/flaschengeist/plugins/balance/models.py b/flaschengeist/plugins/balance/models.py
index 4a967d5..5219751 100644
--- a/flaschengeist/plugins/balance/models.py
+++ b/flaschengeist/plugins/balance/models.py
@@ -8,15 +8,33 @@ from flaschengeist.models import ModelSerializeMixin, UtcDateTime
 
 class Transaction(db.Model, ModelSerializeMixin):
     __tablename__ = "balance_transaction"
+    id: int = db.Column("id", db.Integer, primary_key=True)
     time: datetime = db.Column(UtcDateTime, nullable=False, default=datetime.now(tz=timezone.utc))
     amount: float = db.Column(db.Numeric(precision=5, scale=2, asdecimal=False), nullable=False)
 
+    # Dummy properties used for JSON serialization (userid instead of full user)
+    sender_id: str = ""
+    receiver_id: str = ""
+    author_id: str = ""
+
+    # Protected foreign key properties
     _receiver_id = db.Column("receiver_id", db.Integer, db.ForeignKey("user.id"))
     _sender_id = db.Column("sender_id", db.Integer, db.ForeignKey("user.id"))
     _author_id = db.Column("author_id", db.Integer, db.ForeignKey("user.id"), nullable=False)
 
-    sender: User = db.relationship("User", foreign_keys=[_sender_id])
-    receiver: User = db.relationship("User", foreign_keys=[_receiver_id])
-    author: User = db.relationship("User", foreign_keys=[_author_id])
+    # Not exported relationships just in backend only
+    sender_: User = db.relationship("User", foreign_keys=[_sender_id])
+    receiver_: User = db.relationship("User", foreign_keys=[_receiver_id])
+    author_: User = db.relationship("User", foreign_keys=[_author_id])
 
-    _id = db.Column("id", db.Integer, primary_key=True)
+    @property
+    def sender_id(self):
+        return self.sender_.userid
+
+    @property
+    def receiver_id(self):
+        return self.receiver_.userid
+
+    @property
+    def author_id(self):
+        return self.author_.userid