There’s no fixed rate limit for calling GET /messages/next, but we recommend avoiding constant polling with a fixed delay (e.g. every 10 seconds), as this is a common inefficiency.
Instead, it's best to retrieve messages in batches. You can poll the endpoint as fast as the interface responds to collect available messages quickly. Once you receive a 204 No Content response (indicating there are no more messages), you can pause before polling again.
This approach helps you process transactions promptly and efficiently, without placing unnecessary load on the interface.