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HTTP 408 Request Timeout
The server timed out waiting for the complete request.
4xx · Client error✓ retryable with backoff
In AI APIs specifically
Large request bodies (long contexts, base64 images) over slow links can trip server read timeouts.
Fix checklist
- Retry — safe by definition since the request never completed.
- Compress or trim oversized payloads.
- Check client-side connection pooling for half-dead sockets.
Retry handler (TypeScript)
async function fetchWithRetry(url: string, init: RequestInit, maxRetries = 5) {
for (let attempt = 0; ; attempt++) {
const res = await fetch(url, init);
// 408 is retryable — back off and try again.
if (res.status !== 408 || attempt >= maxRetries) return res;
const retryAfter = Number(res.headers.get("retry-after"));
const delay = Number.isFinite(retryAfter) && retryAfter > 0
? retryAfter * 1000
: Math.min(60_000, 1000 * 2 ** attempt) * (0.5 + Math.random()); // expo backoff + jitter
await new Promise((r) => setTimeout(r, delay));
}
}Spec: RFC reference
Related status codes
400 Bad Request
The server cannot process the request due to a client error — malformed JSON, invalid parameters, or schema violations..
401 UnauthorizedAuthentication is missing or invalid for this request..
402 Payment RequiredThe request requires payment — billing is not set up or a balance is exhausted..
403 ForbiddenThe server understood the request but refuses to authorize it — valid credentials, insufficient permission..