Rate limits

Per-API-key rate limits. Each key has its own bucket — no shared quotas across keys or IPs.

Bucket	Limit
Default	300 requests / minute / key

When a key exceeds its bucket, requests return 429 Too Many Requests with a Retry-After header indicating how many seconds to wait.

429Too Many Requests

{
  "statusCode": 429,
  "message": "ThrottlerException: Too Many Requests"
}

Best practices

Implement exponential backoff with jitter on 429 responses.
Honor the Retry-After header.
Cache responses where possible — /materials and /processes data is updated infrequently.
Need higher limits? Email support@circa.ai.