In the context of webhooks, an application that interacts with a webhook can be described as a Listener or Receiver:
* Listener: The application waits for incoming HTTP POST requests sent by the webhook.
* Receiver: The application receives the data payloads from the webhook when certain events occur.
Reference:
Cisco DevNet Associate Certification Guide: Chapter on Webhooks and Event-Driven Programming.
Webhook documentation and best practices.