Current v1 delivery
Create a price watch for a canonical product, target price, currency, and notification email. The current public v1 contract manages email watches; it does not expose a public webhook registration endpoint.
Manage the full watch lifecycle
Use the same X-Price-Compare-Client-Id when listing, creating, updating, and deleting watches. Store the returned watch ID. Update the target when the customer changes the rule and delete the watch when delivery is no longer wanted.