Rate limits

Requests are rate-limited per API key. Exceeding a limit returns 429 Too Many Requests; wait and retry.

Window	Limit (per key)
1 second	10 requests
10 seconds	30 requests
60 seconds	100 requests

The three endpoints that send a document to a customer are limited further, in addition to the limits above:

Endpoint	Limit
POST /txndata/sendTxn	3 per 10 minutes
POST /txndata/sendPayment	3 per 10 minutes
POST /txndata/sendTxnWP	5 per 10 minutes

Use incremental sync and bulk endpoints (bulkDeleteTxn, deleteContacts, …) to stay well inside the limits. Retry 429 responses with exponential backoff.