How to Handle 500K POST Requests/sec in Express.js (Best Practices)

Can Express.js handle hundreds of thousands of POST requests per second? The short answer is yes — with the right setup.

In this guide, we’ll show you how to efficiently scale your Express app to support 200k–500k POST requests per second, using best practices in body parsing, load balancing, proxy tuning, and security.

🚦 Why Express.js Needs Tuning for High-Traffic APIs

Out of the box, Express is simple and powerful—but not production-optimized for ultra-high volumes. When you're dealing with streaming payloads or burst traffic, every millisecond counts.

🔧 Key Areas to Optimize

Let’s break down the areas where optimization matters most.

✅ 1. Body Parser Configuration

For high-throughput POST requests, the default body parser settings aren’t ideal.

Use raw or text parsers if payloads are simple:

app.use(express.raw({ type: '*/*', limit: '10kb' }));

Tips:

• Set limit to the expected payload size (e.g. '10kb')
• Avoid using express.json() unless you absolutely need structured parsing
• If you use compression, apply it conditionally to avoid wasting CPU

✅ 2. Use a Reverse Proxy (NGINX) Wisely

Place NGINX or HAProxy in front of your Express server to handle:

• Load balancing
• Rate limiting
• Buffering

NGINX config example:

worker_processes auto;
events {
    worker_connections 65535;
    multi_accept on;
}
http {
    client_max_body_size 10k;
    keepalive_timeout 15;
    proxy_buffering off;

    server {
        listen 80;
        location / {
            proxy_pass http://localhost:3000;
            proxy_http_version 1.1;
            proxy_set_header Connection '';
        }
    }
}

✅ 3. Cluster Your App with PM2 or Node’s Native Cluster

Use all CPU cores to parallelize the request handling.

import cluster from 'cluster';
import os from 'os';

if (cluster.isPrimary) {
  for (let i = 0; i < os.cpus().length; i++) {
    cluster.fork();
  }
} else {
  app.listen(3000);
}

Tip: PM2 makes this easier with one command:

pm2 start app.js -i max

✅ 4. Use a Fast Logger (or Disable It in Prod)

Logging slows down the event loop. Use fast loggers like Pino and avoid logging full payloads.

✅ 5. Protect Against Payload Abuse

When you receive massive POST requests, you must validate and limit what gets processed.

• Limit content types (e.g. application/json or application/octet-stream)
• Reject requests over a certain size
• Use a security middleware like helmet
• Use express-rate-limit to throttle by IP

import rateLimit from 'express-rate-limit';

const limiter = rateLimit({
  windowMs: 1000, // 1 second
  max: 1000       // limit each IP to 1000 requests per second
});

app.use(limiter);

🏗️ Suggested Architecture for High-Volume POST APIs

1. Client sends raw data
2. NGINX (handles TLS, buffering, limits)
3. Node Cluster / PM2 (scales across CPUs)
4. Fast Parsers (express.raw, pino)
5. Worker Queue (BullMQ, RabbitMQ for long tasks)
6. Database / Cache (insert/update logic offloaded)

📈 Real-World Tips

• Use Redis or Kafka to offload processing
• Run stress tests with Artillery or wrk
• Prefer stateless design (no in-memory sessions)
• Avoid blocking code — no fs.readFileSync, etc.

🔚 Conclusion

Express can handle high-traffic APIs — even up to 500K POST requests/sec — if you tune it right. With fast body parsers, a good proxy like NGINX, and clustering, you're set for production-grade scale.

Want to build your next high-performance API?

👉 Visit TrendPulseZone.com for more expert dev guides.