diff --git a/cms/README.md b/cms/README.md
index fd18b2f..9caa0e8 100644
--- a/cms/README.md
+++ b/cms/README.md
@@ -92,6 +92,9 @@ Dann: Admin `…:8080/admin/` · Live `…:8080/` · Preview `…:8080/_preview/
 `cd admin && npm install && npm run dev` (Vite-Devserver, proxyt `/api` +
 `/_preview` an den laufenden Container auf :8080).
 
+Tests der API (ohne DB/Container, reine Logik): `cd api && npm test`
+(`node --test` — Pfad-Sicherheit, Rollen/Auth, Rate-Limit, Build-Coalescing).
+
 ### Demo-Inhalt fürs Forum (optional)
 
 `db/seed-demo.sql` füllt die Forum-Kategorien mit ein paar Beispiel-Threads und
diff --git a/cms/api/package.json b/cms/api/package.json
index 158abed..61c6a14 100644
--- a/cms/api/package.json
+++ b/cms/api/package.json
@@ -6,7 +6,8 @@
   "description": "Headless CMS backend für OPENBUREAU — schreibt Supabase-Posts in Hugo-content/, baut und serviert die Site.",
   "scripts": {
     "start": "node src/index.js",
-    "dev": "node --watch src/index.js"
+    "dev": "node --watch src/index.js",
+    "test": "node --test"
   },
   "dependencies": {
     "@hono/node-server": "^1.13.7",
diff --git a/cms/api/src/coalesce.js b/cms/api/src/coalesce.js
new file mode 100644
index 0000000..0bf73d2
--- /dev/null
+++ b/cms/api/src/coalesce.js
@@ -0,0 +1,39 @@
+// Serialisiert asynchrone Aufgaben je `key` und koalesziert Wartende:
+// - Es läuft nie mehr als eine Aufgabe pro Key gleichzeitig.
+// - Kommen während eines Laufs weitere Aufrufe rein, wird GENAU EIN weiterer
+//   Durchlauf nachgelagert (egal wie viele warten) — sie teilen sich dessen
+//   Ergebnis. So sehen alle den jüngsten Stand, ohne einen Lauf-Sturm.
+//
+// Einsatz: teure, idempotente Vorgänge wie der Hugo-Build (siehe hugo.js).
+const state = new Map();
+
+export function coalesce(key, fn) {
+  let s = state.get(key);
+  if (!s) { s = { running: false, rerun: false, fn, waiters: [] }; state.set(key, s); }
+  s.fn = fn;   // jüngste Variante gewinnt für den nächsten Lauf
+  return new Promise((resolve, reject) => {
+    s.waiters.push({ resolve, reject });
+    if (!s.running) drain(key);
+    else s.rerun = true;
+  });
+}
+
+async function drain(key) {
+  const s = state.get(key);
+  s.running = true;
+  try {
+    do {
+      s.rerun = false;
+      const waiters = s.waiters;
+      s.waiters = [];
+      try {
+        const r = await s.fn();
+        waiters.forEach((w) => w.resolve(r));
+      } catch (e) {
+        waiters.forEach((w) => w.reject(e));
+      }
+    } while (s.rerun);
+  } finally {
+    s.running = false;
+  }
+}
diff --git a/cms/api/src/dialog-store.js b/cms/api/src/dialog-store.js
index c128ff6..1bd94a6 100644
--- a/cms/api/src/dialog-store.js
+++ b/cms/api/src/dialog-store.js
@@ -19,7 +19,15 @@ export async function profileFor(email) {
 
 // Library-Beiträge als Threads in der Kategorie „Beiträge" spiegeln, damit man
 // auf jeden Beitrag einen Dialog starten kann. Idempotent (upsert über key).
-export async function syncLibrary() {
+//
+// Gedrosselt: Reads rufen das bei jedem Forum-Aufruf, aber der eigentliche
+// Sync (DB + Filesystem-Walk + Upsert) läuft höchstens alle SYNC_TTL ms.
+// `force: true` (z.B. nach Publish) überspringt die Drosselung.
+const SYNC_TTL = 60_000;
+let lastSync = 0;
+export async function syncLibrary({ force = false } = {}) {
+  if (!force && Date.now() - lastSync < SYNC_TTL) return;
+  lastSync = Date.now();
   const { data: forum } = await supabase
     .from('forums').select('id').eq('slug', LIBRARY_SLUG).single();
   if (!forum) return;
diff --git a/cms/api/src/hugo.js b/cms/api/src/hugo.js
index 4590c25..f5180eb 100644
--- a/cms/api/src/hugo.js
+++ b/cms/api/src/hugo.js
@@ -1,5 +1,6 @@
 import { execFile } from 'node:child_process';
 import { promisify } from 'node:util';
+import { coalesce } from './coalesce.js';
 
 const execFileP = promisify(execFile);
 const SITE_DIR = process.env.SITE_DIR || '/site';
@@ -16,6 +17,13 @@ export async function hugoBuild({ dest, drafts = false } = {}) {
   return { stdout, stderr };
 }
 
+// Koaleszierter Build je Ziel: nie zwei `hugo`-Prozesse für dasselbe dest
+// parallel; schnelle Folge-Aufrufe lösen nur einen nachgelagerten Build aus.
+// Publish (public), Preview (preview) und Profil teilen sich diesen Weg.
+export function buildSite({ dest, drafts = false } = {}) {
+  return coalesce(`build:${dest}:${drafts ? 'd' : 'p'}`, () => hugoBuild({ dest, drafts }));
+}
+
 // Optionaler Git-Backup beim Publish (GIT_PUBLISH=true). Schlägt nie hart fehl —
 // das Publish soll an einem Git-Problem nicht scheitern.
 export async function gitCommit(message) {
diff --git a/cms/api/src/routes/preview.js b/cms/api/src/routes/preview.js
index 50c814e..bf2ec75 100644
--- a/cms/api/src/routes/preview.js
+++ b/cms/api/src/routes/preview.js
@@ -1,6 +1,6 @@
 import { Hono } from 'hono';
 import { urlFor, safeRel } from '../files.js';
-import { hugoBuild } from '../hugo.js';
+import { buildSite } from '../hugo.js';
 
 // Echte Hugo-Vorschau: ganze Site mit --buildDrafts nach preview/ bauen und die
 // URL des Eintrags zurückgeben (so erscheinen auch draft:true-Einträge).
@@ -10,7 +10,7 @@ preview.post('/', async (c) => {
   const { path: rel } = await c.req.json();
   try {
     const safe = safeRel(rel);
-    const build = await hugoBuild({ dest: 'preview', drafts: true });
+    const build = await buildSite({ dest: 'preview', drafts: true });
     return c.json({ ok: true, url: `/_preview${urlFor(safe)}`, hugo: build.stdout });
   } catch (e) {
     return c.json({ error: String(e.message || e) }, 500);
diff --git a/cms/api/src/routes/profile.js b/cms/api/src/routes/profile.js
index 425cf87..68c4a35 100644
--- a/cms/api/src/routes/profile.js
+++ b/cms/api/src/routes/profile.js
@@ -2,7 +2,7 @@ import { Hono } from 'hono';
 import { readFile, writeFile, mkdir, stat } from 'node:fs/promises';
 import path from 'node:path';
 import matter from 'gray-matter';
-import { hugoBuild } from '../hugo.js';
+import { buildSite } from '../hugo.js';
 
 // Profile als Hugo-Data-Datei (data/authors.json) + öffentliche Autor-Seite
 // (content/authors/<slug>.md), gerendert von layouts/authors/single.html.
@@ -19,20 +19,6 @@ function slugify(s) {
 }
 async function exists(p) { try { await stat(p); return true; } catch { return false; } }
 
-// Hugo-Build koaleszieren: nie zwei parallel, und schnelle Folge-Speicherungen
-// lösen nur EINEN nachgelagerten Build aus (verhindert Build-Sturm/DoS).
-let building = false, rerun = false;
-async function rebuildSite() {
-  if (building) { rerun = true; return; }
-  building = true;
-  try {
-    do {
-      rerun = false;
-      await hugoBuild({ dest: 'public', drafts: false }).catch((e) => console.error('[profile] build:', e?.message || e));
-    } while (rerun);
-  } finally { building = false; }
-}
-
 const profile = new Hono();
 
 profile.get('/', async (c) => {
@@ -61,7 +47,7 @@ profile.put('/', async (c) => {
     const page = matter.stringify(bio || '', { title: name, avatar: avatar || '' });
     await writeFile(path.join(AUTHORS_DIR, `${slug}.md`), page, 'utf8');
     // Live bauen (koalesziert), damit die Seite + Byline-Links sofort wirken.
-    await rebuildSite();
+    await buildSite({ dest: 'public', drafts: false }).catch((e) => console.error('[profile] build:', e?.message || e));
   }
 
   return c.json({ ok: true, slug });
diff --git a/cms/api/src/routes/publish.js b/cms/api/src/routes/publish.js
index 3ab3944..efd8fc8 100644
--- a/cms/api/src/routes/publish.js
+++ b/cms/api/src/routes/publish.js
@@ -1,6 +1,7 @@
 import { Hono } from 'hono';
 import { urlFor, safeRel } from '../files.js';
-import { hugoBuild, gitCommit } from '../hugo.js';
+import { buildSite, gitCommit } from '../hugo.js';
+import { syncLibrary } from '../dialog-store.js';
 
 // Publizieren: public/ neu bauen (ohne Drafts) → live. Optional git-commit.
 const publish = new Hono();
@@ -9,7 +10,9 @@ publish.post('/', async (c) => {
   const { path: rel } = await c.req.json();
   try {
     const safe = safeRel(rel);
-    const build = await hugoBuild({ dest: 'public', drafts: false });
+    const build = await buildSite({ dest: 'public', drafts: false });
+    // Neue/aktualisierte Library-Beiträge sofort als Dialog-Threads spiegeln.
+    await syncLibrary({ force: true }).catch(() => {});
     const git = await gitCommit(`cms: publish ${safe}`).catch((e) => ({ error: String(e.message || e) }));
     return c.json({ ok: true, url: urlFor(safe), git, hugo: build.stdout });
   } catch (e) {
diff --git a/cms/api/test/auth.test.js b/cms/api/test/auth.test.js
new file mode 100644
index 0000000..a51aeb3
--- /dev/null
+++ b/cms/api/test/auth.test.js
@@ -0,0 +1,68 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+
+// Env vor dem Import setzen: supabase.js bricht ohne URL/Key ab, ADMIN_EMAILS
+// und JWT_SECRET werden beim Modul-Load gelesen.
+process.env.SUPABASE_URL ||= 'http://localhost';
+process.env.SUPABASE_SERVICE_KEY ||= 'dummy';
+process.env.JWT_SECRET = 'test-secret';
+process.env.ADMIN_EMAILS = 'boss@x.ch';
+
+const { roleOf, requireAuth } = await import('../src/auth.js');
+const { sign } = await import('hono/jwt');
+
+test('roleOf: Admin aus ADMIN_EMAILS', () => {
+  assert.equal(roleOf({ email: 'boss@x.ch' }), 'admin');
+  assert.equal(roleOf({ email: 'BOSS@X.CH' }), 'admin');
+});
+
+test('roleOf: Rolle aus app_metadata', () => {
+  assert.equal(roleOf({ email: 'a@x.ch', app_metadata: { role: 'admin' } }), 'admin');
+  assert.equal(roleOf({ email: 'a@x.ch', app_metadata: { role: 'editor' } }), 'editor');
+  assert.equal(roleOf({ email: 'a@x.ch' }), 'user');
+});
+
+// Minimaler Hono-Kontext-Stub.
+function fakeCtx(authHeader) {
+  const store = {};
+  return {
+    req: { header: (h) => (h === 'Authorization' ? authHeader : undefined) },
+    set: (k, v) => { store[k] = v; },
+    get: (k) => store[k],
+    json: (body, status = 200) => ({ __status: status, body }),
+  };
+}
+
+test('requireAuth: gültiges Token wird lokal verifiziert', async () => {
+  const token = await sign(
+    { sub: 'u1', email: 'A@x.ch', app_metadata: { role: 'editor' }, exp: Math.floor(Date.now() / 1000) + 60 },
+    'test-secret', 'HS256');
+  let passed = false;
+  const c = fakeCtx('Bearer ' + token);
+  await requireAuth(c, async () => { passed = true; });
+  assert.equal(passed, true);
+  assert.equal(c.get('email'), 'a@x.ch');           // kleingeschrieben
+  assert.equal(c.get('role'), 'editor');
+  assert.equal(c.get('canModerate'), true);
+  assert.equal(c.get('isAdmin'), false);
+});
+
+test('requireAuth: fehlendes Token → 401', async () => {
+  const c = fakeCtx('');
+  const r = await requireAuth(c, async () => { throw new Error('darf nicht laufen'); });
+  assert.equal(r.__status, 401);
+});
+
+test('requireAuth: kaputtes/falsch signiertes Token → 401', async () => {
+  const bad = await sign({ sub: 'u1', exp: Math.floor(Date.now() / 1000) + 60 }, 'falsches-secret', 'HS256');
+  for (const t of ['Bearer garbage', 'Bearer ' + bad]) {
+    const r = await requireAuth(fakeCtx(t), async () => { throw new Error('darf nicht laufen'); });
+    assert.equal(r.__status, 401);
+  }
+});
+
+test('requireAuth: abgelaufenes Token → 401', async () => {
+  const expired = await sign({ sub: 'u1', exp: Math.floor(Date.now() / 1000) - 10 }, 'test-secret', 'HS256');
+  const r = await requireAuth(fakeCtx('Bearer ' + expired), async () => { throw new Error('darf nicht laufen'); });
+  assert.equal(r.__status, 401);
+});
diff --git a/cms/api/test/coalesce.test.js b/cms/api/test/coalesce.test.js
new file mode 100644
index 0000000..3f9bfeb
--- /dev/null
+++ b/cms/api/test/coalesce.test.js
@@ -0,0 +1,46 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+
+const { coalesce } = await import('../src/coalesce.js');
+
+const tick = (ms = 5) => new Promise((r) => setTimeout(r, ms));
+
+test('coalesce: nie mehr als ein Lauf gleichzeitig pro Key', async () => {
+  let active = 0, maxActive = 0, runs = 0;
+  const fn = async () => { active++; maxActive = Math.max(maxActive, active); await tick(10); runs++; active--; return runs; };
+
+  // 5 gleichzeitige Aufrufe.
+  await Promise.all(Array.from({ length: 5 }, () => coalesce('k1', fn)));
+  assert.equal(maxActive, 1, 'parallele Läufe');
+  // Erster Lauf bedient den ersten Aufruf; die 4 während des Laufs eingetroffenen
+  // teilen sich GENAU EINEN nachgelagerten Lauf → insgesamt 2.
+  assert.equal(runs, 2);
+});
+
+test('coalesce: Wartende teilen sich das Ergebnis des nachgelagerten Laufs', async () => {
+  let n = 0;
+  const fn = async () => { await tick(10); return ++n; };
+  const first = coalesce('k2', fn);          // startet sofort → Ergebnis 1
+  await tick(2);                              // sicherstellen, dass er läuft
+  const a = coalesce('k2', fn);              // wartet → nachgelagerter Lauf
+  const b = coalesce('k2', fn);              // wartet → selber Lauf wie a
+  assert.equal(await first, 1);
+  const [ra, rb] = await Promise.all([a, b]);
+  assert.equal(ra, 2);
+  assert.equal(rb, 2);                        // a und b teilen sich Lauf 2
+});
+
+test('coalesce: Fehler wird an die Wartenden propagiert, Key bleibt nutzbar', async () => {
+  let fail = true;
+  const fn = async () => { await tick(5); if (fail) throw new Error('boom'); return 'ok'; };
+  await assert.rejects(() => coalesce('k3', fn), /boom/);
+  fail = false;
+  assert.equal(await coalesce('k3', fn), 'ok');   // danach wieder verwendbar
+});
+
+test('coalesce: verschiedene Keys laufen unabhängig', async () => {
+  const fn = async () => { await tick(5); return 'done'; };
+  const [x, y] = await Promise.all([coalesce('kA', fn), coalesce('kB', fn)]);
+  assert.equal(x, 'done');
+  assert.equal(y, 'done');
+});
diff --git a/cms/api/test/files.test.js b/cms/api/test/files.test.js
new file mode 100644
index 0000000..10b7955
--- /dev/null
+++ b/cms/api/test/files.test.js
@@ -0,0 +1,41 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+
+const { safeRel, normAuthors, hasAccess, urlFor } = await import('../src/files.js');
+
+test('safeRel: gültiger relativer .md-Pfad bleibt erhalten', () => {
+  assert.equal(safeRel('library/software/stack.md'), 'library/software/stack.md');
+  assert.equal(safeRel('a/./b.md'), 'a/b.md');
+});
+
+test('safeRel: Path-Traversal wird abgelehnt', () => {
+  assert.throws(() => safeRel('../etc/passwd.md'));
+  assert.throws(() => safeRel('a/../../b.md'));
+  assert.throws(() => safeRel('/absolut.md'));
+});
+
+test('safeRel: nur .md erlaubt, leer/falsch wirft', () => {
+  assert.throws(() => safeRel('note.txt'));
+  assert.throws(() => safeRel(''));
+  assert.throws(() => safeRel(null));
+});
+
+test('normAuthors: String/Array/Leer normalisieren', () => {
+  assert.deepEqual(normAuthors('a@x.ch'), ['a@x.ch']);
+  assert.deepEqual(normAuthors(['a@x.ch', 'b@y.ch']), ['a@x.ch', 'b@y.ch']);
+  assert.deepEqual(normAuthors(null), []);
+  assert.deepEqual(normAuthors([]), []);
+});
+
+test('hasAccess: case-insensitive Mitgliedschaft', () => {
+  assert.equal(hasAccess(['Karim@x.ch'], 'karim@x.ch'), true);
+  assert.equal(hasAccess(['a@x.ch'], 'b@y.ch'), false);
+  assert.equal(hasAccess([], 'a@x.ch'), false);
+});
+
+test('urlFor: Hugo-URLs aus relativem Pfad', () => {
+  assert.equal(urlFor('_index.md'), '/');
+  assert.equal(urlFor('manifest.md'), '/manifest/');
+  assert.equal(urlFor('library/software/stack.md'), '/library/software/stack/');
+  assert.equal(urlFor('software/_index.md'), '/software/');
+});
diff --git a/cms/api/test/ratelimit.test.js b/cms/api/test/ratelimit.test.js
new file mode 100644
index 0000000..4907b52
--- /dev/null
+++ b/cms/api/test/ratelimit.test.js
@@ -0,0 +1,44 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+
+const { rateLimit } = await import('../src/ratelimit.js');
+
+function fakeCtx() {
+  const headers = {};
+  return {
+    req: { header: () => undefined },
+    header: (k, v) => { headers[k] = v; },
+    json: (body, status = 200) => ({ __status: status, body }),
+    _headers: headers,
+  };
+}
+
+test('rateLimit: blockt nach Überschreiten mit 429 + Retry-After', async () => {
+  const mw = rateLimit({ max: 2, windowMs: 10_000, keyFn: () => 'fix' });
+  let calls = 0;
+  const run = async () => { const c = fakeCtx(); const r = await mw(c, async () => { calls++; }); return { c, r }; };
+
+  assert.equal((await run()).r, undefined);   // 1 → durch (next, kein Return)
+  assert.equal((await run()).r, undefined);   // 2 → durch
+  const { c, r } = await run();               // 3 → blockiert
+  assert.equal(r.__status, 429);
+  assert.ok(c._headers['Retry-After']);
+  assert.equal(calls, 2);                      // next nur zweimal aufgerufen
+});
+
+test('rateLimit: getrennte Schlüssel zählen getrennt', async () => {
+  let key = 'a';
+  const mw = rateLimit({ max: 1, windowMs: 10_000, keyFn: () => key });
+  assert.equal((await mw(fakeCtx(), async () => {})), undefined);      // a:1 ok
+  assert.equal((await mw(fakeCtx(), async () => {})).__status, 429);   // a:2 blockiert
+  key = 'b';
+  assert.equal((await mw(fakeCtx(), async () => {})), undefined);      // b:1 ok
+});
+
+test('rateLimit: Fenster läuft ab → wieder frei', async () => {
+  const mw = rateLimit({ max: 1, windowMs: 30, keyFn: () => 'win' });
+  assert.equal((await mw(fakeCtx(), async () => {})), undefined);
+  assert.equal((await mw(fakeCtx(), async () => {})).__status, 429);
+  await new Promise((r) => setTimeout(r, 40));
+  assert.equal((await mw(fakeCtx(), async () => {})), undefined);      // Fenster neu
+});