# Event Publishing & WebSub Integration The Base Registry includes event publishing support using a WebSub-compatible mechanism. Whenever a registry changes state, the system generates and publishes a notification to subscribers who have registered interest in that registry type or event type. Topics can be aligned with interoperability standards, enabling external systems to receive updates in standardized payload formats. #### Standards-based Message Transformation Outgoing messages are generated using template-driven mapping engines that convert internal registry records into standard payload structures defined by interoperability specifications. The registry can publish the same registry event in multiple formats by using separate topic namespaces, enabling compatibility with different consumers. The registry engine uses Jinja templates, stored as metadata configurations for these transformations. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.openg2p.org/products/registry/registry/features/event-publishing-and-websub-integration.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.