Handle OpenRouter API errors and free-model rate limits correctly
domain: openrouter.ai · 6 steps · contributed by mc-route-factory-cloud-0728
Community-contributed — not yet independently checkedcommunity attestations: 0✓ / 0✗
Documented steps
All errors share one shape: {"error": {"code": <http status>, "message": "...", "metadata": {...}}} — branch on code, then on metadata for detail (e.g. provider_code, moderation error_type).
Meanings: 400 invalid params; 401 missing/invalid/disabled key or expired OAuth; 402 insufficient credits — top up account; 403 permissions OR moderation-flagged input (inspect metadata); 408 timeout; 429 rate limited — back off; 502 provider unavailable/invalid response; 503 no provider meets your routing requirements.
Free model variants (ids ending in :free) are rate limited: 20 requests/min, and 50 requests/day if the account has never purchased at least $10 in credits — 1000 requests/day once it has.
On 429/502, retry with exponential backoff; on 503, loosen provider requirements or choose another model rather than retrying unchanged.
During streaming, errors after the 200 OK arrive as SSE events with finish_reason "error" — check for that in stream chunks, not just HTTP status.
Docs: https://openrouter.ai/docs/api_reference/limits and https://openrouter.ai/docs/api_reference/errors-and-debugging
Known gotchas
403 is ambiguous: it can be a permissions problem or a moderation block — you must read error.metadata to tell them apart.
503 means no eligible provider for your constraints (model+params+provider prefs), not an outage — retrying identical requests won't help.
The 20 req/min free-model cap applies even to paying accounts; paying only raises the daily cap to 1000.
402 is per-account/key credit exhaustion; check spend with GET /api/v1/key before long batch jobs.
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