EP.85 Building a WebSocket Server with GraphQL Subscriptions in Golang

In this episode, we’ll explore GraphQL Subscriptions — a modern approach to building real-time applications using WebSocket that offers flexible control over data structure and avoids the common issue of over-fetching data seen with traditional REST APIs.

Ideal use cases include:

• 🟢 Real-time Chat Systems
• 🔔 Notifications
• 📊 Live Dashboards

🤔 Why Use GraphQL Subscriptions?

🧪 GraphQL Subscriptions with WebSocket in Go

Here’s a basic server setup using gqlgen, a popular Go library for building GraphQL servers.

package main

import (
    "log"
    "net/http"

    "github.com/99designs/gqlgen/graphql/handler"
    "github.com/99designs/gqlgen/graphql/playground"
    "github.com/yourusername/yourproject/graph"
    "github.com/yourusername/yourproject/graph/generated"
)

func main() {
    srv := handler.NewDefaultServer(
        generated.NewExecutableSchema(
            generated.Config{Resolvers: &graph.Resolver{}},
        ),
    )

    http.Handle("/", playground.Handler("GraphQL Playground", "/query"))
    http.Handle("/query", srv)

    log.Println("🚀 Server running at http://localhost:8080/")
    log.Fatal(http.ListenAndServe(":8080", nil))
}

✅ Note: This example uses gqlgen, one of the most efficient tools to create GraphQL servers in Go.

🗨 Sample Subscription Query

subscription {
  messageAdded {
    id
    content
    sender
  }
}

Whenever a new message is added (e.g., a user sends a chat), all clients subscribed to messageAdded will receive the new data instantly via WebSocket.

⚙️ Connecting to WebSocket (Frontend with Apollo Client)

You can use tools like Apollo Client, which natively supports GraphQL subscriptions:

import { WebSocketLink } from "@apollo/client/link/ws";
import { ApolloClient, InMemoryCache } from "@apollo/client";

const wsLink = new WebSocketLink({
  uri: `ws://localhost:8080/query`,
  options: {
    reconnect: true
  }
});

const client = new ApolloClient({
  link: wsLink,
  cache: new InMemoryCache()
});

💡 Apollo handles connection_init, ping/pong, and automatic reconnect out of the box.

🧠 Summary

Using GraphQL Subscriptions with WebSocket is a powerful approach for building real-time applications with better control over data flow and structure. Benefits include:

• Fine-grained payload control
• No repetitive polling
• Easy schema adjustments
• Seamless integration with Go via gqlgen

🚀 Give it a Try!

Try applying this to build:

• ✅ A real-time group chat
• ✅ Order or system notifications
• ✅ Live reporting dashboard

🔜 Next EP

EP.86: Managing WebSocket Connections with Redis Pub/Sub

We’ll learn how to scale your WebSocket Server across multiple instances using Redis Pub/Sub to keep all users in sync — no matter which server they're connected to!

Read more

• Golang The Series

• JS2GO

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