Rate limits
60 requests per minute per key.
60 requests per minute, per key. Build for that ceiling: pace the calls, and do not let one client burst against it.
Treat it as a limit and not as a target. On writes there is a second ceiling that matters more, and it is your plan's credit balance.
Going over answers 429, with a Retry-After: 60 header:
{ "error": { "code": "rate_limited", "message": "too many requests: the limit is 60 requests per minute per API key" } }