Reverse Proxy

A reverse proxy sits between clients and backend servers, forwarding client requests to the appropriate server.

Forward Proxy vs Reverse Proxy

Forward Proxy (client-side):
Client --> Proxy --> Internet
(Hides client identity)

Reverse Proxy (server-side):
Internet --> Proxy --> Server
(Hides server identity)

What a Reverse Proxy Does

1. Hides backend servers — Clients don't know which server handles their request
2. SSL termination — Handles HTTPS encryption/decryption
3. Load balancing — Distributes requests across servers
4. Caching — Caches responses for performance
5. Compression — Compresses responses
6. Security — Filters malicious requests

Why Reverse Proxies Matter

Without Reverse Proxy:
Client --> Server 1 (exposed)
Client --> Server 2 (exposed)
Client --> Server 3 (exposed)

With Reverse Proxy:
Client --> Reverse Proxy --> Server 1 (hidden)
                         --> Server 2 (hidden)
                         --> Server 3 (hidden)

Security Benefits

• Backend servers are not directly exposed to the internet
• DDoS protection at the proxy level
• Rate limiting before requests reach your app
• SSL/TLS handled once at the proxy

Common Reverse Proxies

• Nginx — Most popular, high performance
• HAProxy — Load balancing focus
• AWS ALB — Managed load balancer/proxy

Key Principles

1. Follow SOLID principles
2. Write clean, readable code
3. Test thoroughly
4. Document decisions
5. Monitor in production

Implementation

• Start simple, refactor as needed
• Use established patterns
• Consider trade-offs
• Review with peers

Continuous Improvement

• Learn from incidents
• Update documentation
• Share knowledge
• Mentor others

Key Points

• Understanding Reverse Proxy is essential for production systems
• Always consider scalability and maintainability
• Test thoroughly before deploying to production
• Monitor performance and set up alerting

Common Patterns

1. Validation: Always validate input at the boundary
2. Error Handling: Use structured error responses
3. Logging: Log key events for debugging
4. Testing: Unit, integration, and load tests
5. Documentation: Keep docs updated with code changes