Rate limits

Per-key and per-agency budgets, the RateLimit headers and 429.

Each call costs units — most cost 1; heavier ones (planning several days, uploads) cost more, as each reference page says. The budgets, per 60-second window:

Every response carries the IETF RateLimit headers for the tighter of the two:

RateLimit-Policy: "key";q=120;w=60
RateLimit: "key";r=87;t=34

r is what is left, t the seconds until the window resets. When a budget runs out the API answers 429 rate_limited with Retry-After in seconds. Wait that long, then retry.