EventSource/eventsource

Health v2 · maintenance only

Adoption not part of the score

1155 stars · 266 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

A WhatWG/W3C-compliant EventSource client library for consuming server-sent events (SSE) in Node.js, browsers, Deno, Bun, and other JavaScript runtimes. It implements the spec with minimal additions and supports reconnection, typed event listeners, and explicit connection closing.

Use cases

• consume server-sent events in node.js
• subscribe to an SSE endpoint from the browser
• listen for real-time updates over HTTP streams
• polyfill EventSource in runtimes without native support
• stream live notifications from a server
• connect to an SSE API with automatic reconnection

When to choose

• you need a spec-compliant EventSource client across Node.js and browsers
• your runtime lacks a native EventSource implementation
• you want a minimal, standards-based SSE consumer
• you need broad runtime support including Deno and Bun

When to avoid

• you need bidirectional streaming or a richer client API (consider eventsource-client)
• you need WebSockets or two-way communication
• you must support very old runtimes without private class fields (use the 4.x branch instead)

Facets

library · maturity stable

http-client websocket web-development frontend backend apis browser bun cross-platform server-sent-events sse eventsource typescript whatwg real-time nodejs deno

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