What this error means
A 529 overloaded_error is server-side back-pressure from Anthropic during demand spikes. It is transient.
How to fix it
- Retry with exponential backoff and jitter
- Fail over to another provider on repeated 529s
- Cap concurrency during known peak windows
Example error message
{
"type": "error",
"error": {
"type": "overloaded_error",
"message": "Overloaded"
}
}Frequently asked
Why 529 and not 503?
Anthropic uses 529 specifically for capacity overload; treat it like a retryable 503.