Authentication
Rate limits
Requests are rate limited per API key. Back off and retry when you're throttled.
Limits
The default is 120 requests per minute per API key. Over the limit, you get 429 Too Many Requests. Respect the standard Retry-After and X-RateLimit-* response headers.
On writes, combine backoff with an idempotency key so a retried request never creates a duplicate invoice.