It is possible to call the remote webservice using a webhook, yes. But if you're running more than, say, 50,000 leads through it per day, you need to take certain limits into account:
- the baseline HTTP request performance of the fastest useful webhook (~75ms) doesn't encourage truly massive daily use
- the performance of this particular webhook is likely much slower than the baseline
- the remote service may limit the number of calls per day
If I were rolling this out, I would be sure to use a caching layer so that repeated calls for the same address during a 24-hour (or 72-hour) period do not have to hit the remote database. An even better/additional way to cache is to have a separate Datetime field like lastConsentInquiryDateTime that stores the timestamp of the last response. Then constrain your calls so someone who's been looked up in the last N days doesn't call the 'hook again and again.