Nginx Reverse Proxy and Load Balancing: Production Configuration Guide

Nginx handles millions of concurrent connections efficiently, making it the ideal reverse proxy and load balancer for production applications. This guide covers real-world configurations.

Basic Reverse Proxy

server {
    listen 80;
    server_name app.example.com;

    location / {
        proxy_pass http://127.0.0.1:3000;
        proxy_http_version 1.1;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;

        # Timeouts
        proxy_connect_timeout 60s;
        proxy_send_timeout 60s;
        proxy_read_timeout 60s;
    }
}

Load Balancing with Health Checks

upstream backend {
    least_conn;    # or: round_robin, ip_hash, hash $request_uri

    server 10.0.0.1:3000 weight=3 max_fails=3 fail_timeout=30s;
    server 10.0.0.2:3000 weight=2 max_fails=3 fail_timeout=30s;
    server 10.0.0.3:3000 backup;    # Only used when others are down
}

server {
    listen 443 ssl http2;
    server_name app.example.com;

    ssl_certificate /etc/letsencrypt/live/app.example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/app.example.com/privkey.pem;

    location / {
        proxy_pass http://backend;
        proxy_next_upstream error timeout http_502 http_503;
        proxy_next_upstream_tries 3;
    }
}

WebSocket Proxy

location /ws {
    proxy_pass http://backend;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_read_timeout 86400s;
    proxy_send_timeout 86400s;
}

Caching Proxy

proxy_cache_path /var/cache/nginx levels=1:2 keys_zone=app_cache:10m
    max_size=1g inactive=60m use_temp_path=off;

server {
    location /api/ {
        proxy_pass http://backend;
        proxy_cache app_cache;
        proxy_cache_valid 200 10m;
        proxy_cache_valid 404 1m;
        proxy_cache_key "$scheme$request_method$host$request_uri";
        add_header X-Cache-Status $upstream_cache_status;
    }
}

Nginx as a reverse proxy handles SSL termination, load balancing, caching, and WebSocket connections — all while using minimal resources. Start with the basics and add complexity as your infrastructure grows.