WebSocket Gateway — Complete Real-Time Gateway Guide

In this tutorial, you will learn about Websocket Gateway. We cover key concepts, practical examples, and best practices to help you master this topic.

WebSocket support in API gateways enables real-time, bidirectional communication between clients and servers. The gateway manages WebSocket connections, upgrades, and message routing.

What You'll Learn

You'll learn how gateways handle WebSocket connections, the challenges of persistent connections, and how to configure WebSocket routing.

Why It Matters

Real-time features (chat, notifications, live updates) require WebSocket or Server-Sent Events. Gateways must support WebSocket to manage these connections alongside traditional REST APIs.

Real-World Use

A live chat application uses AWS API Gateway WebSocket API. The gateway manages 100,000 concurrent connections. When a user sends a message, the gateway routes it to the chat service, which broadcasts to all connected clients in the room.

Implementation

# Kong WebSocket configuration
services:
  - name: chat-service
    url: ws://chat-service:3000
    protocol: ws
    routes:
      - name: chat-route
        paths:
          - /ws/chat
        strip_path: false
        protocols:
          - ws
          - wss

plugins:
  - name: jwt
    config:
      uri_param_names:
        - jwt
      claims_to_verify:
        - exp

# NGINX WebSocket proxy
server {
    location /ws/ {
        proxy_pass http://websocket-backend:3000;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_set_header Host $host;
        proxy_read_timeout 86400s;
        proxy_send_timeout 86400s;
    }
}

Common Mistakes

| Mistake | Fix | |---------|-----| | Timeout too short | WebSocket connections dropped | Set proxy_read_timeout to 24h | | No sticky sessions | Broadcast to wrong client | Use consistent routing per connection ID | | Not handling connection failures | Clients not notified of disconnect | Implement reconnection logic client-side | | Scaling WebSocket connections | One gateway instance overloaded | Use Redis pub/sub for multi-instance broadcasting | | Authentication not validated on connect | Unauthorized WebSocket connections | Validate token during WebSocket handshake |

What's Next

Complete the API Gateway Project.