Rate limits

Authenticated API requests are limited to 60 per second per team. Every response carries:

Header	Meaning
X-RateLimit-Limit	The per-second limit (60)
X-RateLimit-Remaining	Requests left in the current second
X-RateLimit-Reset	Unix time when the window resets

Exceeding the limit returns 429 with name: "rate_limit_exceeded"; wait for the reset and retry.

Two things this limit is not:

• It’s not your sending quota. Monthly email volume is separate; see GET /usage and quota_exceeded.
• It’s not per key. All keys on a team share the same bucket.

If you’re bumping into it while sending, batch sending moves up to 100 emails per request.