Rate limits

Each key can make 120 requests a minute (a sliding window). Every response carries:

• RateLimit-Limit: requests allowed in the window
• RateLimit-Remaining: requests left
• RateLimit-Reset: seconds until another request is allowed

Past the limit you get 429 with code rate_limited, a Retry-After header and retryAfter in the body. Wait that many seconds, then carry on.