Building Blocks
Reverse Proxy
Understanding reverse proxies and their role in system architecture.
2 min readConcepts · System Design
What is a Reverse Proxy?
A Reverse Proxy sits in front of backend servers and forwards client requests to them. Unlike a forward proxy (which acts on behalf of clients), a reverse proxy acts on behalf of servers.
Forward vs Reverse Proxy
Reverse Proxy Functions
1. Load Balancing
Distribute requests across multiple backend servers.
2. SSL Termination
Handle HTTPS encryption/decryption at the proxy:
3. Caching
Cache responses to reduce backend load:
4. Compression
Compress responses before sending to clients.
5. Security
- Hide backend server details
- Filter malicious requests
- Rate limiting
- Web Application Firewall (WAF)
Common Use Cases
| Use Case | How Reverse Proxy Helps |
|---|---|
| API Gateway | Route to different microservices |
| Static content | Serve cached files |
| SSL offloading | Centralized certificate management |
| A/B testing | Route traffic to different versions |
Popular Reverse Proxies
| Software | Strengths |
|---|---|
| NGINX | High performance, widely used |
| HAProxy | Load balancing focus |
| Traefik | Container-native, auto-discovery |
| Envoy | Service mesh, observability |
NGINX Example
server {
listen 80;
server_name example.com;
location /api/ {
proxy_pass http://backend-servers;
}
location /static/ {
root /var/www/static;
}
}Interview Tips
- Differentiate forward vs reverse proxy
- Know common functions: SSL termination, caching, load balancing
- Mention security benefits
- Give examples: NGINX, HAProxy, cloud load balancers
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