Rate limits

Limits are per key, not per IP address, so one integration cannot throttle another.

Every response carries RateLimit-Limit, RateLimit-Remaining, and RateLimit-Reset — not just the ones that get throttled — so you can slow down before you are stopped. A 429 also carries Retry-After in seconds.

Batching is the cheapest fix: one call with 500 records costs one request, where 500 calls cost 500.