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Webhooks

Updated Aug 02, 2021 ·

Working with Webhooks​

Webhooks send real-time notifications to your application when specific events happen. They avoid repeated polling and make applications more efficient.

  • Send HTTP POST requests to a registered URL
  • Triggered by specific events
  • Allow multiple applications to subscribe

Webhooks are sometimes called reverse APIs because the server calls your application instead of your application requesting data. You register a URI with the webhook provider, and when the event occurs, the provider sends an HTTP request to that URI.

Examples:

  • Cisco DNA Center can send a webhook to your app when a network device becomes unreachable. Your app receives the outage details in JSON format and can act immediately.
  • Cisco Webex Teams can notify your app whenever a new message is posted in a room. Your app receives the message automatically instead of polling the Teams API.

Consuming a Webhook​

To use a webhook, your application must meet basic requirements:

  • The application must be running to receive HTTP POST requests
  • The application must provide a registered URI to the webhook provider

Your application must also handle incoming notifications properly. This includes validating the request, processing the payload, and responding with a 2xx HTTP status to acknowledge receipt.

There are free online tools called webhook testers that help you check if your application can receive and process webhook requests. These tools also let you preview the notification content, which is useful during development and testing.