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Webhooks overview

Understand inbound versus outbound webhooks and when to use each.

In short​

A webhook is an automated HTTP callback that lets the platform and your own systems notify each other the moment something happens, instead of one side repeatedly polling the other. There are two directions to think about: outbound webhooks, where the platform sends an event to a URL you host, and inbound webhooks, where your systems send data to an endpoint the platform exposes.

Why it matters​

Webhooks keep your data in sync in near real time without scheduled batch jobs or constant API polling. Common uses:

  • Stream delivery and engagement events (delivered, opened, clicked, bounced, unsubscribed) into your CRM, data warehouse, or analytics stack.
  • Trigger downstream workflows the instant a subscriber acts on a Broadcast.
  • Push subscriber updates or events from your systems into the platform to drive automation.

The payoff is fresher data, fewer moving parts, and no wasted API calls.

How it works​

Outbound (platform to you): You register an HTTPS endpoint and select which events to receive. When an event occurs, the platform sends an HTTP POST with a JSON payload describing what happened. Your endpoint should respond quickly with a 2xx status; most systems queue the payload and process it asynchronously. Expect retries on failure, so make your handler idempotent (safe to receive the same event more than once). Verify authenticity using the signing secret or signature header provided when you register (confirm the exact steps in your account).

Inbound (you to platform): You POST to a platform-provided URL, authenticating with your API credentials, to hand off events or subscriber data.

A simple outbound example: a subscriber clicks a link in a Broadcast, and within seconds your endpoint receives a click event containing the subscriber identifier, the Edition, and the target URL — which your app writes straight to the contact's timeline.

Canonical terms: Author, Edition, Folder (Project Folder), Broadcast. See the Glossary.