Anthropic “Overloaded” error (529)
Overloaded
A 529 “Overloaded” means Anthropic’s API is temporarily over capacity. It’s on their side, not yours. Retry with backoff, and add a fallback model so your app keeps working during spikes.
What causes it
- High demand on Anthropic’s API during peak periods.
- No fallback configured, so one provider being busy stalls everything.
How to fix it
- Retry with exponential backoff; overload is usually brief.
- Configure a fallback model/provider so requests reroute when Claude is busy.
- Avoid retry storms that pile on while the API is recovering.
Running an agent? Agents that hard-pin a single provider stall completely on a 529. Auto-failover keeps them running through provider spikes.
Keep working on a fixed monthly plan
Standard Compute retries transient upstream errors and can fall back to another provider for the same model behind the same endpoint, so fewer overload errors reach your agent and you don’t configure fallbacks yourself.
Plans from $19 a month with $19 of compute. Eligible new accounts can try $0.25 of compute first, no card. Trial terms
FAQ
Is a 529 my fault?
No. 529 means the provider is over capacity. The only client-side fix is to retry and to have a fallback so you’re not dependent on one provider’s spare capacity.