Realtime

Server-Sent Events (SSE)

A unidirectional server-to-client streaming protocol over HTTP, defined by the WHATWG HTML Living Standard. SSE is simpler than WebSocket — it reuses HTTP and supports automatic reconnection — but is one-way only. It has seen a resurgence as the carrier for LLM token streams from OpenAI, Anthropic, and other AI APIs.

GitHub

Documentation

📖
Documentation
https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events

Other Resources

🔗
Specification
https://html.spec.whatwg.org/multipage/server-sent-events.html

Work with this as data

Every API here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for apis

7 MCP tools reach this
  • find_apisBrowse and filter every API in the catalog.
  • get_api_artifactsOne API's artifacts, grouped by type.
  • get_openapiThe primary OpenAPI for this API.
  • find_similar_apisAPIs that look like this one.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools

Call it yourself

curl for this page
This API 
curl "https://apis.io/api/v1/apis/server-sent-events"
All apis 
curl "https://apis.io/api/v1/apis?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no email required.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.

API entry from apis.yml

apis.yml Raw ↑ 
aid: realtime:server-sent-events
name: Server-Sent Events (SSE)
description: A unidirectional server-to-client streaming protocol over HTTP, defined by the WHATWG HTML
  Living Standard. SSE is simpler than WebSocket — it reuses HTTP and supports automatic reconnection
  — but is one-way only. It has seen a resurgence as the carrier for LLM token streams from OpenAI, Anthropic,
  and other AI APIs.
humanURL: https://html.spec.whatwg.org/multipage/server-sent-events.html
baseURL: https://
tags:
- SSE
- Server-Sent Events
- Protocol
- Unidirectional
- Standard
properties:
- type: Specification
  url: https://html.spec.whatwg.org/multipage/server-sent-events.html
- type: Documentation
  url: https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events