How to use reverse proxies effectively

· Category: System Design

Short answer

A reverse proxy sits between clients and backend servers, handling cross-cutting concerns like security, performance, and request routing.

Steps

  1. Terminate TLS at the proxy to offload cryptographic work from applications.
  2. Compress responses with gzip or brotli to reduce bandwidth.
  3. Cache static content and common API responses to improve latency.
  4. Route requests to different backends based on path, host, or headers.
  5. Apply access controls, rate limiting, and request filtering.

Tips

  • Use a reverse proxy to centralize logging and observability.
  • Configure keepalive connections to backends to reduce TCP overhead.
  • Employ WebSocket support if the proxy needs to handle persistent connections.
  • Regularly update the proxy software to patch security vulnerabilities.

Common issues

  • Reverse proxy becoming a single point of failure without redundancy.
  • Buffering large requests or responses causing memory pressure.
  • Incorrect header forwarding breaking client IP detection.
  • Complex routing rules becoming difficult to maintain.

Example

# Consistent hashing for service discovery
import hashlib

def get_node(key, nodes):
    hash_val = int(hashlib.md5(key.encode()).hexdigest(), 16)
    return nodes[hash_val % len(nodes)]

node = get_node('user-123', ['node-a', 'node-b', 'node-c'])

This snippet implements consistent hashing to distribute keys across nodes, a foundational technique in scalable distributed systems.