diff --git a/server/index.ts b/server/index.ts
index 847c3e7..6db0c71 100644
--- a/server/index.ts
+++ b/server/index.ts
@@ -6,7 +6,11 @@ import { existsSync } from 'node:fs';
 import path from 'node:path';
 import os from 'node:os';
 import { fileURLToPath } from 'node:url';
-import { runClaude, type ClaudeFieldSpec } from './claudeRunner.ts';
+import {
+  runClaude,
+  type ClaudeFieldSpec,
+  type ClaudeFormResponse,
+} from './claudeRunner.ts';
 
 const PORT = Number(process.env.PORT ?? 3001);
 const HOST = process.env.HOST ?? '127.0.0.1';
@@ -37,6 +41,26 @@ const upload = multer({
   },
 });
 
+// Langläufer-Jobs: claude -p dauert 30–120s+. Würde die HTTP-Verbindung so
+// lange offen gehalten, kappt jeder Reverse-Proxy (oder ein kurzer Netz-
+// Hänger) sie und der Browser bekommt nur "Failed to fetch". Stattdessen
+// kehrt POST sofort mit einer Job-ID zurück, das Frontend pollt per GET.
+type Job =
+  | { status: 'pending'; createdAt: number }
+  | { status: 'done'; createdAt: number; result: ClaudeFormResponse }
+  | { status: 'error'; createdAt: number; error: string };
+
+const jobs = new Map<string, Job>();
+const JOB_TTL_MS = 15 * 60 * 1000;
+
+// Abgelaufene Jobs regelmäßig aufräumen, damit die Map nicht wächst.
+setInterval(() => {
+  const now = Date.now();
+  for (const [id, job] of jobs) {
+    if (now - job.createdAt > JOB_TTL_MS) jobs.delete(id);
+  }
+}, 60 * 1000).unref();
+
 const app = express();
 
 app.post(
@@ -83,11 +107,12 @@ app.post(
     const tempDir = path.join(os.tmpdir(), `rentenv-${requestId}`);
     const formName = filenameForMime('form', formFile.mimetype);
 
+    // Quelldateien schreiben — Fehler hier sind echte 5xx (kein claude-Lauf).
+    const sourceNames: string[] = [];
     try {
       await mkdir(tempDir, { recursive: true });
       await writeFile(path.join(tempDir, formName), formFile.buffer);
 
-      const sourceNames: string[] = [];
       for (let i = 0; i < sourceFiles.length; i++) {
         const f = sourceFiles[i];
         const name = filenameForMime(`source_${i + 1}`, f.mimetype);
@@ -98,28 +123,72 @@ app.post(
       if (sourceText.length > 0) {
         await writeFile(path.join(tempDir, 'source_text.txt'), sourceText);
       }
-
-      const result = await runClaude(tempDir, {
-        formFilename: formName,
-        sourceFilenames: sourceNames,
-        hasSourceText: sourceText.length > 0,
-        fields: fieldSpecs,
-      });
-      res.json(result);
     } catch (e: unknown) {
-      next(e);
-    } finally {
       if (existsSync(tempDir)) {
         rm(tempDir, { recursive: true, force: true }).catch(() => {});
       }
+      next(e);
+      return;
     }
+
+    // Job registrieren und SOFORT antworten — claude läuft im Hintergrund.
+    jobs.set(requestId, { status: 'pending', createdAt: Date.now() });
+    res.status(202).json({ jobId: requestId });
+
+    runClaude(tempDir, {
+      formFilename: formName,
+      sourceFilenames: sourceNames,
+      hasSourceText: sourceText.length > 0,
+      fields: fieldSpecs,
+    })
+      .then((result) => {
+        jobs.set(requestId, {
+          status: 'done',
+          createdAt: Date.now(),
+          result,
+        });
+      })
+      .catch((e: unknown) => {
+        const msg = e instanceof Error ? e.message : String(e);
+        console.error('[claude job error]', requestId, msg);
+        jobs.set(requestId, {
+          status: 'error',
+          createdAt: Date.now(),
+          error: msg,
+        });
+      })
+      .finally(() => {
+        if (existsSync(tempDir)) {
+          rm(tempDir, { recursive: true, force: true }).catch(() => {});
+        }
+      });
   }
 );
 
+// Status/Ergebnis eines Jobs. Bewusst kurze Requests -> proxy-sicher.
+app.get('/api/process/:jobId', (req: Request, res: Response) => {
+  const job = jobs.get(req.params.jobId);
+  if (!job) {
+    res
+      .status(404)
+      .json({ error: 'Job nicht gefunden (abgelaufen oder Server neugestartet).' });
+    return;
+  }
+  if (job.status === 'pending') {
+    res.json({ status: 'pending' });
+    return;
+  }
+  if (job.status === 'error') {
+    res.json({ status: 'error', error: 'Claude CLI failed', details: job.error });
+    return;
+  }
+  res.json({ status: 'done', result: job.result });
+});
+
 app.use((err: unknown, _req: Request, res: Response, _next: NextFunction) => {
   const msg = err instanceof Error ? err.message : String(err);
   console.error('[server error]', msg);
-  res.status(502).json({ error: 'Claude CLI failed', details: msg });
+  res.status(500).json({ error: 'Serverfehler beim Vorbereiten', details: msg });
 });
 
 app.get('/api/health', (_req, res) => {
diff --git a/services/api.ts b/services/api.ts
index 8600ed5..099b586 100644
--- a/services/api.ts
+++ b/services/api.ts
@@ -33,16 +33,85 @@ export async function processDocuments(
   });
 
   if (!res.ok) {
-    let message = `Server antwortete mit ${res.status}`;
-    try {
-      const data = await res.json();
-      if (data?.error) message = data.error;
-      if (data?.details) message += ` — ${data.details}`;
-    } catch {
-      // fall through
-    }
-    throw new Error(message);
+    throw new Error(await errorMessageFrom(res));
   }
 
-  return (await res.json()) as FormResponse;
+  const { jobId } = (await res.json()) as { jobId?: string };
+  if (!jobId) throw new Error('Server hat keine Job-ID zurückgegeben.');
+
+  return pollJob(jobId);
+}
+
+const POLL_INTERVAL_MS = 2000;
+const MAX_WAIT_MS = 6 * 60 * 1000;
+const MAX_CONSECUTIVE_NETWORK_ERRORS = 8;
+
+// Pollt den Job-Status. Kurze Requests -> ein Proxy-Timeout oder ein kurzer
+// Netz-Hänger killt nicht mehr die ganze Analyse, sondern wird einfach beim
+// nächsten Tick erneut versucht.
+async function pollJob(jobId: string): Promise<FormResponse> {
+  const start = Date.now();
+  let networkErrors = 0;
+
+  while (true) {
+    if (Date.now() - start > MAX_WAIT_MS) {
+      throw new Error('Zeitüberschreitung beim Warten auf die Analyse.');
+    }
+    await delay(POLL_INTERVAL_MS);
+
+    let res: Response;
+    try {
+      res = await fetch(`/api/process/${jobId}`);
+      networkErrors = 0;
+    } catch {
+      // "Failed to fetch" beim Pollen = transient -> weiter versuchen.
+      if (++networkErrors >= MAX_CONSECUTIVE_NETWORK_ERRORS) {
+        throw new Error(
+          'Verbindung zum Server verloren. Läuft der Backend-Container noch?'
+        );
+      }
+      continue;
+    }
+
+    if (res.status === 404) {
+      throw new Error(
+        'Analyse-Job nicht mehr vorhanden (Server neugestartet?). Bitte erneut versuchen.'
+      );
+    }
+    if (!res.ok) {
+      throw new Error(await errorMessageFrom(res));
+    }
+
+    const data = (await res.json()) as {
+      status?: 'pending' | 'done' | 'error';
+      result?: FormResponse;
+      error?: string;
+      details?: string;
+    };
+
+    if (data.status === 'pending') continue;
+    if (data.status === 'done' && data.result) return data.result;
+    if (data.status === 'error') {
+      let message = data.error ?? 'Claude CLI failed';
+      if (data.details) message += ` — ${data.details}`;
+      throw new Error(message);
+    }
+    throw new Error('Unerwartete Antwort vom Server.');
+  }
+}
+
+function delay(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+async function errorMessageFrom(res: Response): Promise<string> {
+  let message = `Server antwortete mit ${res.status}`;
+  try {
+    const data = await res.json();
+    if (data?.error) message = data.error;
+    if (data?.details) message += ` — ${data.details}`;
+  } catch {
+    // fall through
+  }
+  return message;
 }