Previous edition: Provider error code distribution, April 2026
Provider error code distribution, October 2026
Provider error code distribution, October 2026
Status codes returned by upstream providers on failed responses (router- and gateway-level rejections excluded).
Auth / quotaClient errorServer errorNot foundGateway / timeout
In October 2026, 429 rate limits made up 66.4% of provider-returned errors on the Requesty gateway.Source: Requesty production gateway. October 2026, status_code_origin = provider, successful = false.
What errors do AI providers return? In October 2026, 429 rate limits made up 66.4% of provider-returned errors on the Requesty gateway. 400 Bad Request was next at 18.5%, and 503 Service Unavailable at 6.3%.
Why it mattersMost provider failures are capacity limits, not outages. That is why fallbacks across providers recover most failed requests.
Period
Oct 2026
Updated
November 11, 2026
ID
status-codes-october-2026
§ 01
Key findings
- 01429 Too Many Requests: 66.4%.
- 02400 Bad Request: 18.5%.
- 03503 Service Unavailable: 6.3%.
- 04404 Not Found: 4.0%.
- 05402 Payment Required: 1.5%.
§ 01b
Questions this answers
- What is the most common LLM API error?
- How often do providers return 429 rate limits?
- How common are 5xx errors from AI providers?
§ 02
Data
| Status code | Description | Bucket | % of rejections(percent) |
|---|---|---|---|
| 429 | Too Many Requests | auth_quota | 66.36% |
| 400 | Bad Request | client_error | 18.50% |
| 503 | Service Unavailable | server_error | 6.28% |
| 404 | Not Found | not_found | 3.96% |
| 402 | Payment Required | auth_quota | 1.45% |
| 500 | Internal Server | server_error | 1.01% |
| 504 | Gateway Timeout | gateway | 0.74% |
| 401 | Unauthorized | auth_quota | 0.59% |
| 502 | Bad Gateway | gateway | 0.42% |
| 410 | Gone | not_found | 0.30% |
| 422 | Unprocessable | client_error | 0.24% |
| 403 | Forbidden | auth_quota | 0.05% |
| 408 | Request Timeout | gateway | 0.04% |
| 529 | Site Overloaded | server_error | 0.03% |
§ 03
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ID: status-codes-october-2026·Updated November 11, 2026·Period Oct 2026