Server-sent events

{{DefaultAPISidebar("Server Sent Events")}} {{AvailableInWorkers}} 

Traditionally, a web page has to send a request to the server to receive new data; that is, the page requests data from the server. With server-sent events, it’s possible for a server to send new data to a web page at any time, by pushing messages to the web page. These incoming messages can be treated as Events + data inside the web page.

[!NOTE] Firefox does not currently support the use of server-sent events in service workers (it does support them in dedicated and shared workers). See Firefox bug 1681218.

Concepts and usage

To learn how to use server-sent events, see our article Using server-sent events.

Interfaces

• {{domxref("EventSource")}} 
  • : Defines all the features that handle connecting to a server, receiving events/data, errors, closing a connection, etc.

Examples

• Simple SSE demo using PHP

Specifications

{{Specifications}} 

See also

Tools

• Mercure: a real-time communication protocol (publish-subscribe) built on top of SSE
• Transmit: a native opinionated Server-Sent-Event (SSE) module built for AdonisJS
• EventSource polyfill for Node.js
• Remy Sharp’s EventSource polyfill
• Yaffle’s EventSource polyfill
• Rick Waldron’s jquery plugin
• intercooler.js declarative SSE support

Related Topics

• Learn: Making network requests with JavaScript
• JavaScript
• WebSockets

Other resources

• Creating a wall/feed social application powered by server-sent events and its code on GitHub.