Webhooks vs polling for verification results
Most verification checks are synchronous, but some are not. When a result lands later, a webhook beats a polling loop.
When results are async
Document-generation checks (RC PDF, DL PDF) and some status lookups can take longer than a request should wait. For these, the API accepts the request and returns a transaction id, then delivers the result out of band.
Why webhooks win
A webhook delivers the result the instant it is ready, with no wasted requests. A polling loop either checks too often (burning rate limit) or too rarely (adding latency). Point a webhook at an endpoint, verify the signature, and process the payload.
Make your endpoint boring
Return 2xx fast, do the real work async, and be idempotent: the same result may be delivered more than once. Verify the HMAC signature on every request so a leaked URL cannot be abused.