Hi Maurice,
Yes, you can receive HTTP requests (via Zapier Webhook) and even use the content of the body. Assuming you’re receiving a JSON. The fields from the JSON can be mapped e.g. to subsequent tasks e.g. Airtable. So you do a lookup in Airtable for a specifc record that matches your criteria.
Now here is the tricky part. Each tasks basically works own its own. The connection to the incoming HTTP request is gone as soon as the first task (webhook) is done. So as far as I know there is no way to return a response within the same call. You could of course send another (independent) HTTP post to any REST service as a subsequent task on its own.
Hope this makes sense to you.