Rate Limits
Claude API rate limits — 429 handling, Retry-After, concurrency protection, and throughput guidance.
LLMsRelay is an independently operated API gateway. It is not affiliated with or endorsed by Anthropic, PBC. Product and model names are used only to describe compatibility.
Status code: 429 Too Many Requests. Header: Retry-After (seconds). Scope: Per-key + global protection. Strategy: Exponential backoff with jitter.
Rate Limiting
The LLMsRelay gateway applies protective limits to preserve service stability under mixed traffic patterns. Enforcement is not a fixed public tier table: it depends on request shape, concurrency, and current gateway load. When you exceed a limit, the API returns a 429 status code along with a Retry-After header.
What is limited
| Scope | What it means |
|---|---|
| Per API key | A key can be throttled independently of other keys. |
| Per-key concurrency | Too many simultaneous long-running requests can trigger 429. |
| Global gateway protection | The gateway can shed load to protect service stability. |
| Attachment-heavy traffic | Large multimodal turns may be treated more strictly than plain text traffic. |
We do not publish a stable numeric RPM/TPM contract for every request shape. If you need sustained higher throughput, contact support with your expected traffic pattern.
Response headers
retry-after— seconds to wait before retrying after a 429
Do not rely on undocumented rate-limit headers as a stable public contract.
Handling 429 Responses
- Implement exponential backoff (start at 1s, double each retry)
- Respect
Retry-Afterheaders when present - Queue requests in your application layer and reduce parallelism when needed
- Be especially conservative with long-running streams and multimodal turns
- Use caching to reduce avoidable repeat traffic