Rate limits - Will This Person Answer

The limit

requests

rolling window

one limit, shared by REST and MCP

You get a 429 rate_limit_exceeded with a Retry-After header of 60 seconds. Nothing is charged for a request that was refused.

429 Too Many Requests

{
  "error": {
    "code": "rate_limit_exceeded",
    "message": "More than 60 requests in 60 seconds."
  }
}

Send one request at a time, or a few in parallel, and wait for Retry-After when you hit a 429.
Use an Idempotency-Key per contact so a retry never charges twice.
For thousands of contacts, upload a CSV in the app instead. It runs in the background and has no rate limit.