Concurrency

2 admitted requests at a time

A client may have 2 admitted requests in flight. A third concurrent request is rejected with 429 concurrency_limit_exceeded and a short Retry-After.

How to stay under it

• Prefer one bulk call over many parallel detail calls.
• Keep a small worker pool (2) rather than firing requests in parallel from a loop.
• Treat concurrency_limit_exceeded as backpressure, not as a failure to retry immediately.

Concurrency is aggregated per client, like every other limit in Quotas.