diff --git a/server/index.js b/server/index.js
index 56b8579..4e22aff 100644
--- a/server/index.js
+++ b/server/index.js
@@ -1,11 +1,36 @@
 const path = require('path');
 const express = require('express');
+const { getDoc, putDoc } = require('./db');
 
 const app = express();
 app.use(express.json({ limit: '5mb' }));
 
+const KEYS = ['employees', 'duties', 'vacation'];
+const EMPTY = { employees: [], duties: {}, vacation: {} };
+
 app.get('/api/health', (req, res) => res.json({ status: 'ok' }));
 
+app.get('/api/state', (req, res) => {
+  const state = { ...EMPTY, updatedAt: null };
+  for (const key of KEYS) {
+    const doc = getDoc(key);
+    if (doc) {
+      state[key] = doc.value;
+      if (!state.updatedAt || doc.updatedAt > state.updatedAt) state.updatedAt = doc.updatedAt;
+    }
+  }
+  res.json(state);
+});
+
+app.put('/api/state', (req, res) => {
+  const body = req.body || {};
+  const now = new Date().toISOString();
+  for (const key of KEYS) {
+    if (body[key] !== undefined) putDoc(key, body[key], now);
+  }
+  res.json({ status: 'ok', updatedAt: now });
+});
+
 // Statisches Frontend (Repo-Root). Dotfiles werden per Default nicht ausgeliefert.
 app.use(express.static(path.join(__dirname, '..')));
 
diff --git a/server/state.test.js b/server/state.test.js
new file mode 100644
index 0000000..b8f76f3
--- /dev/null
+++ b/server/state.test.js
@@ -0,0 +1,42 @@
+const { test } = require('node:test');
+const assert = require('node:assert');
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+
+process.env.DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), 'dp-state-'));
+const app = require('./index');
+
+async function req(port, method, body) {
+  const opts = { method, headers: { 'Content-Type': 'application/json' } };
+  if (body) opts.body = JSON.stringify(body);
+  const res = await fetch(`http://127.0.0.1:${port}/api/state`, opts);
+  return { status: res.status, body: await res.json() };
+}
+
+test('leerer Server liefert leeren State', async () => {
+  const server = app.listen(0);
+  const { port } = server.address();
+  try {
+    const { status, body } = await req(port, 'GET');
+    assert.strictEqual(status, 200);
+    assert.deepStrictEqual(body.employees, []);
+    assert.deepStrictEqual(body.duties, {});
+    assert.deepStrictEqual(body.vacation, {});
+    assert.strictEqual(body.updatedAt, null);
+  } finally { server.close(); }
+});
+
+test('PUT dann GET Roundtrip', async () => {
+  const server = app.listen(0);
+  const { port } = server.address();
+  try {
+    const put = await req(port, 'PUT', { employees: ['Max'], duties: { Max: { '2026-07': [] } } });
+    assert.strictEqual(put.status, 200);
+    assert.strictEqual(put.body.status, 'ok');
+    const get = await req(port, 'GET');
+    assert.deepStrictEqual(get.body.employees, ['Max']);
+    assert.deepStrictEqual(get.body.duties, { Max: { '2026-07': [] } });
+    assert.strictEqual(typeof get.body.updatedAt, 'string');
+  } finally { server.close(); }
+});