About Web Sockets and Event Subscriptions

Applications can subscribe to events by using a web socket connection to the REST API, but there are several limitations:

  • Only Sawtooth block-commit and state-delta events are supported.

  • You cannot specify a single event type or use filters to fine-tune the results. A web socket subscription returns all events.

  • Event catch-up is not available.

We recommend using ZMQ for event subscription, as described in Using ZMQ to Subscribe to Events.

For information on using web sockets, see State Delta Subscriptions via Web Sockets.