Server-Sent Events in Go

Server-sent events (SSE) is a technology where a browser receives automatic updates from a server via HTTP connection. It is not websockets. Learn more.

Nick Message
Join the SSE real-time chat

◼︎ Users
◼︎ Inbound messages / sec
◼︎ Outbound messages / sec

Realtime server Go stats

Memory usage

◼︎ Heap bytes
◼︎ Stack bytes

Allocations per second

◼︎ Mallocs / sec
◼︎ Frees / sec

MIT Open Sourced

Server-side (Go)

func streamRoom(c *gin.Context) {
    roomid := c.ParamValue("roomid")
    listener := openListener(roomid)
    statsTicker := time.NewTicker(1 * time.Second)
    defer closeListener(roomid, listener)
    defer statsTicker.Stop()

    c.Stream(func(w io.Writer) bool {
        select {
        case msg := <-listener:
            c.SSEvent("message", msg)
        case <-statsTicker.C:
            c.SSEvent("stats", Stats())
        return true

Client-side (JS)

function StartSSE(roomid) {
    var source = new EventSource('/stream/'+roomid);
    source.addEventListener('message', newChatMessage, false);
    source.addEventListener('stats', stats, false);

SSE package

import ""

func httpHandler(w http.ResponseWriter, req *http.Request) {
    // data can be a primitive like a string, an integer or a float
    sse.Encode(w, sse.Event{
        Event: "message",
        Data:  "some data\nmore data",

    // also a complex type, like a map, a struct or a slice
    sse.Encode(w, sse.Event{
        Id:    "124",
        Event: "message",
        Data: map[string]interface{}{
            "user":    "manu",
            "date":    time.Now().Unix(),
            "content": "hi!",
event: message
data: some data\\nmore data

id: 124
event: message
data: {"content":"hi!","date":1431540810,"user":"manu"}