Server-Sent Events

SSE effectively provides an efficient form of XHR Streaming, where a device can subscribe for updates from a server.

What are Server-Sent Events?


SSE is a push technology commonly used to send unidirectional message updates or continuous data streams to a browser client. SSE aims to enhance native, cross-browser server-to-client streaming through a JavaScript API called EventSource, standardized as part of HTML5 by the World Wide Web Consortium (W3C).

The Ably SSE and raw HTTP streaming API provides a way to get a realtime stream of events from Ably in circumstances where using a full Ably Realtime client library, or even an MQTT library, is impractical.