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Subscriptions

A subscription is a configuration that tells Hook0 where to deliver events and which events to deliver. Subscriptions connect your webhook endpoints to the events they care about.

Key Points​

  • Subscriptions belong to an Application
  • Each subscription specifies a target URL and filtering criteria
  • Filtering is based on Event Types and Labels
  • Subscriptions can be enabled or disabled without deletion
  • Each subscription has a secret for signature verification

How Subscriptions Work​

Event arrives at Hook0
         |
         v
+-------------------+
|  Match Event Type |
+-------------------+
         |
         v
+-------------------+
|   Match Labels    |
+-------------------+
         |
         v
+-------------------+
| Create Request    |
| Attempt           |
+-------------------+
         |
         v
    Deliver to
   Subscription
      Target

Filtering Criteria​

Subscriptions filter incoming events using two mechanisms:

Event Type Filtering​

Subscribe to specific event types (e.g., order.created, user.updated). Only events with matching types trigger deliveries.

Label Filtering​

Further refine which events to receive using labels. For example, a subscription with label tenant_id: "acme" only receives events that have that exact label.

Both filters must match for an event to be delivered.

Target Types​

Subscriptions support HTTP targets where webhooks are delivered via POST (or other methods) to your endpoint. The target configuration includes:

  • URL - Where to send the webhook
  • HTTP Method - Typically POST
  • Headers - Custom headers to include

Subscription Secrets​

Each subscription has an associated secret used to sign webhook payloads. Recipients use this secret to verify:

  • The webhook came from Hook0
  • The payload wasn't modified in transit
  • The webhook is fresh (timestamp validation)

Benefits​

  • Real-Time Notifications - Immediate updates when events occur
  • Decoupled Architecture - Separate concerns between event producers and consumers
  • Selective Delivery - Only receive events you care about
  • Automated Actions - Trigger workflows, emails, or database updates

Use Cases​

Webhook subscriptions enable automation across many domains:

  • E-commerce - Order notifications, inventory updates, shipping alerts
  • Payments - Transaction confirmations, refund notifications
  • CRM - New customer alerts, profile updates
  • DevOps - Deployment notifications, monitoring alerts
  • Healthcare - Appointment reminders, record updates

What's Next?​