diff --git a/app.py b/app.py
new file mode 100644
index 0000000..1d75691
--- /dev/null
+++ b/app.py
@@ -0,0 +1,90 @@
+import json
+import os
+import uuid
+from datetime import datetime
+from flask import Flask, render_template, request, jsonify
+
+app = Flask(__name__)
+DATA_DIR = os.path.join(os.path.dirname(__file__), 'data')
+os.makedirs(DATA_DIR, exist_ok=True)
+
+def list_projects():
+    projects = []
+    for f in os.listdir(DATA_DIR):
+        if f.endswith('.json'):
+            path = os.path.join(DATA_DIR, f)
+            with open(path) as fp:
+                data = json.load(fp)
+            projects.append({
+                'id': f.replace('.json', ''),
+                'name': data.get('name', 'Unbenannt'),
+                'updated': data.get('updated', ''),
+                'rooms': len(data.get('rooms', []))
+            })
+    projects.sort(key=lambda p: p['updated'], reverse=True)
+    return projects
+
+def load_project(pid):
+    path = os.path.join(DATA_DIR, f'{pid}.json')
+    if not os.path.exists(path):
+        return None
+    with open(path) as fp:
+        return json.load(fp)
+
+def save_project(pid, data):
+    data['updated'] = datetime.now().isoformat()
+    path = os.path.join(DATA_DIR, f'{pid}.json')
+    with open(path, 'w') as fp:
+        json.dump(data, fp, indent=2, ensure_ascii=False)
+
+@app.route('/')
+def index():
+    return render_template('index.html')
+
+@app.route('/api/projects')
+def api_projects():
+    return jsonify(list_projects())
+
+@app.route('/api/projects', methods=['POST'])
+def api_create_project():
+    body = request.get_json() or {}
+    pid = str(uuid.uuid4())[:8]
+    data = {
+        'name': body.get('name', 'Neuer Grundriss'),
+        'created': datetime.now().isoformat(),
+        'updated': datetime.now().isoformat(),
+        'rooms': [],
+        'grid_size': 20  # cm per grid cell
+    }
+    save_project(pid, data)
+    return jsonify({'id': pid, **data})
+
+@app.route('/api/projects/<pid>')
+def api_get_project(pid):
+    data = load_project(pid)
+    if not data:
+        return jsonify({'error': 'Projekt nicht gefunden'}), 404
+    return jsonify({'id': pid, **data})
+
+@app.route('/api/projects/<pid>', methods=['PUT'])
+def api_update_project(pid):
+    data = load_project(pid)
+    if not data:
+        return jsonify({'error': 'Projekt nicht gefunden'}), 404
+    body = request.get_json() or {}
+    if 'name' in body:
+        data['name'] = body['name']
+    if 'rooms' in body:
+        data['rooms'] = body['rooms']
+    save_project(pid, data)
+    return jsonify({'id': pid, **data})
+
+@app.route('/api/projects/<pid>', methods=['DELETE'])
+def api_delete_project(pid):
+    path = os.path.join(DATA_DIR, f'{pid}.json')
+    if os.path.exists(path):
+        os.remove(path)
+    return jsonify({'status': 'ok'})
+
+if __name__ == '__main__':
+    app.run(host='0.0.0.0', port=5000, debug=True)