𝗧𝗵𝗲 𝗚𝗮𝘁𝗲𝘄𝗮𝘆 𝗟𝗮𝘆𝗲𝗿 𝗘𝘅𝗽𝗹𝗮𝗶𝗻𝗲𝗱
Most backend engineers use reverse proxies, load balancers, and API gateways. Few explain the difference.
Tools like Nginx, Kong, and Envoy do all three. This blurs the lines. You need a mental model to make sense of it.
The gateway layer sits in front of your backend. It controls, inspects, and routes traffic.
Reverse Proxy It protects one server.
- SSL Termination: It handles HTTPS. Your backend focuses on business logic.
- Caching: It stores common responses to reduce server load.
- Compression: It shrinks data before sending it to users.
- IP Hiding: It keeps your server IP secret.
Load Balancer It distributes traffic across many servers.
- Health Checks: It stops traffic to dead servers.
- L4 Balancing: Fast. Routes by IP and port.
- L7 Balancing: Smart. Routes by HTTP headers and paths.
API Gateway It manages microservices complexity.
- Central Auth: Validates tokens in one place.
- Rate Limiting: Enforces traffic rules everywhere.
- Transformation: Converts data formats like XML to JSON.
- Versioning: Routes /v1 to old and /v2 to new services.
How to choose?
- 1 server? Use a reverse proxy.
- Scaling out? Add a load balancer.
- Microservices? Add an API gateway.
- 20+ services? Use a service mesh.
Do not over-architect. Solve the problem you have today. Build for where you are. Layer as you grow.