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Getting started with schemas

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EventCatalog supports any schema or specification format, including (but not limited to):

  • JSON / YAML
  • Avro
  • Protobuf
  • GraphQL
  • OpenAPI
  • AsyncAPI

Schemas are optional, but they add valuable context to your messages and services by making data structures explicit and discoverable.

Why add schemas?​

By adding schemas to your messages and services, you unlock several benefits:

  • Schema Explorer – Quickly find and browse schemas (see demo)
  • Fields Explorer – Browse every schema field catalog-wide, search across formats, and trace fields to the services that produce and consume them (see guide)
  • API access – Access schemas programmatically through the EventCatalog API (see guide)
  • Ask questions – Query and explore schemas using the EventCatalog MCP
  • Visualization – Help developers understand data structures using schema property search and visualization
  • Field Usage – Track which services depend on specific fields to understand the impact of schema changes (see guide)

Adding schemas to messages​

You can attach one or more schemas to any message type:

  • Commands -
  • Queries
  • Events

Get started by following the relevant guide:

Adding specifications to services​

In addition to message-level schemas, services can render full API and messaging specifications, including:

  • AsyncAPI
  • OpenAPI
  • GraphQL

Use the guides below to add specifications to your services: