alepha@docs:~/docs/reference/primitives$
cat $sse.md | pretty
2 min read

#$sse

#Import

typescript 
1import { $sse } from "alepha/server";

#Overview

Creates a Server-Sent Events (SSE) primitive for streaming typed events to clients.

SSE endpoints provide a unidirectional stream from server to client over HTTP, with full type safety for event data. The handler receives emit() and close() functions to control the stream.

Key Features

  • Full TypeScript inference for event data types
  • Automatic schema validation using TypeBox
  • Convention-based URL generation with customizable paths
  • Direct invocation (run()) returns an SseStream async iterable
  • HTTP requests (fetch()) returns an SseFetchResponse async iterable
  • Built-in text/event-stream content-type handling

URL Generation

All $sse paths are automatically prefixed with /api.

ts 
1$sse({ path: "/events" })     // POST /api/events2$sse({ path: "/feed/:id" })   // POST /api/feed/:id

The HTTP method is always POST.

#Options

Option Type Required Description
name string No Name of the SSE endpoint.
group string No Group SSE endpoints together.
path string No Pathname of the route
schema TConfig No The config schema for the SSE endpoint.
description string No A short description of the endpoint
disabled boolean No Disable the SSE endpoint.
handler SseHandler<TConfig> Yes Main SSE handler

#Examples

ts 
 1class NotificationController { 2  events = $sse({ 3    schema: { 4      data: t.object({ 5        type: t.text(), 6        message: t.text(), 7      }), 8    }, 9    handler: async ({ emit, close }) => {10      emit({ type: "welcome", message: "Connected!" });11      // ... stream events ...12      close();13    },14  });15}