diff --git a/flaschengeist/app.py b/flaschengeist/app.py
index 057b177..7e4c8d2 100644
--- a/flaschengeist/app.py
+++ b/flaschengeist/app.py
@@ -1,7 +1,7 @@
 import pkg_resources
 from flask import Flask, current_app
 from flask_cors import CORS
-from datetime import datetime
+from datetime import datetime, date
 from flask.json import JSONEncoder, jsonify
 from werkzeug.exceptions import HTTPException
 
@@ -19,7 +19,7 @@ class CustomJSONEncoder(JSONEncoder):
         except AttributeError:
             pass
 
-        if isinstance(o, datetime):
+        if isinstance(o, datetime) or isinstance(o, date):
             return o.isoformat()
 
         # Check if iterable
diff --git a/flaschengeist/models/user.py b/flaschengeist/models/user.py
index 689c592..eec15d6 100644
--- a/flaschengeist/models/user.py
+++ b/flaschengeist/models/user.py
@@ -1,3 +1,6 @@
+from datetime import date
+from typing import Optional
+
 from sqlalchemy.orm.collections import attribute_mapped_collection
 
 from . import ModelSerializeMixin
@@ -42,14 +45,16 @@ class User(db.Model, ModelSerializeMixin):
         firstname: Firstname of the User
         lastname: Lastname of the User
         mail: mail address of the User
+        birthday: Birthday of the user
     """
 
     __tablename__ = "user"
     userid: str = db.Column(db.String(30), nullable=False)
     display_name: str = db.Column(db.String(30))
-    firstname: str = db.Column(db.String(50))
-    lastname: str = db.Column(db.String(50))
-    mail: str = db.Column(db.String(60))
+    firstname: str = db.Column(db.String(50), nullable=False)
+    lastname: str = db.Column(db.String(50), nullable=False)
+    mail: str = db.Column(db.String(60), nullable=False)
+    birthday: Optional[date] = db.Column(db.Date)
     roles: [str] = []
 
     roles_: [Role] = db.relationship("Role", secondary=association_table, cascade="save-update, merge")
diff --git a/run_flaschengeist b/run_flaschengeist
index e7419cb..23f338a 100644
--- a/run_flaschengeist
+++ b/run_flaschengeist
@@ -9,7 +9,7 @@ import pkg_resources
 class InterfaceGenerator:
     known = []
     classes = {}
-    mapper = {"str": "string", "int": "number", "float": "number", "datetime": "Date", "NoneType": "null"}
+    mapper = {"str": "string", "int": "number", "float": "number", "date": "Date", "datetime": "Date", "NoneType": "null"}
 
     def __init__(self, namespace, filename):
         self.basename = ""