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Metadata

Metadata lets you attach arbitrary key-value data to events and subscriptions. Hook0 stores it but does not act on it -- it's for your own use.

Key points​

  • Metadata can be attached to events and subscriptions
  • Hook0 stores it but does not process it
  • Searchable via the Search API
  • Not visible to webhook consumers unless you explicitly include it

Metadata vs labels​

A common question: when should you use metadata instead of labels?

Use labels when you need to route events to specific subscriptions. Use metadata when you need to store extra context for your own systems.

Common use cases​

  • Correlation IDs to link events to external systems
  • User context (the user ID who triggered the event)
  • Debug info like request IDs or trace identifiers
  • Domain-specific identifiers

Description field​

A separate description field exists for human-readable annotations. For example: "Customer onboarding webhook for Acme Corp".

Security

Don't store sensitive information (bank accounts, card details, passwords) in metadata or the description field.

What's next?​