Reference

Rate limits

Two axes: requests per second (per API key) and credit budget (per account). Exceeding either returns 429.

Per-plan request rates

Plan	/v1/validate	/v1/batch	Other
Free	10/min	3/min	60/min
Starter	50/s	30/min	300/min
Growth	200/s	60/min	600/min
Scale	500/s	120/min	1,200/min
Enterprise	Uncapped	Uncapped	Uncapped

Auth endpoint hardening

Regardless of plan, per-IP:

POST /auth/wise-link: 5 requests / 10 minutes.
POST /auth/register: 20 requests / hour.
POST /auth/login: 30 requests / 10 minutes.

429 response

HTTP

HTTP/1.1 429 Too Many Requests
Retry-After: 42
Content-Type: application/json

{
  "error": {
    "code": "RATE_LIMITED",
    "message": "Too many requests. Try again in 42s.",
    "details": { "retryAfter": 42 }
  }
}

Best practices

Honour Retry-After. Exponential backoff on top.
Batch API is per-minute-throttled; single-validate is per-second. Choose accordingly for bulk work.
Use Idempotency-Key so retries don't double-charge.
For sustained high volume — upgrade the plan or contact sales for a custom ceiling.