Reverse Proxy
A reverse proxy sits between clients and one or more web servers, intercepting their requests and handing them off to the right backend. It handles SSL termination, load balancing, and caching before any responses go back to users. Forward proxies work for clients; reverse proxies work for servers. It's a vital element of web server architecture and API gateway design.
Quick Facts
- Also known as
- Inbound proxy, gateway proxy
- IP source
- Server-side infrastructure (not residential IPs)
- Detection risk
- Low , appears as the origin server to end clients
- Typical use
- Load balancing, SSL termination, DDoS mitigation, API gateway routing
- Price range
- Infrastructure cost varies; Geonode residential proxies start at $0.27/GB
How a reverse proxy works
The client sends a request, and the reverse proxy grabs it first. Then it picks which backend server should handle the load, using a load balancer so no single server gets hammered. It manages SSL certificates at the edge, a process called SSL termination. Backend servers don't touch encryption this way. Clients only see the reverse proxy's address, hiding the inner server setup.
Reverse Proxy vs. Forward Proxy
Forward proxies sit in front of the client and hide their identity while sending traffic (like Geonode's service with 2.5M+ residential IPs in 195+ countries). But a reverse proxy sits in front of servers to shield backend infrastructure, manage load balancing, and handle SSL termination. Forward proxies can't do this.
Why this is different
Advantages
- Hides origin server identity from clients. No nonsense.
- Spreads the load across backend servers. Simple but effective.
- Chops off SSL/TLS overhead at the edge, saving 15-20% CPU on backend servers. It's all about efficiency.
- Caches static content at the edge. Slashes origin server load by 40-70% for asset-heavy traffic.
Tradeoffs
- Mess one thing up and you've exposed all your backends. It's brutal but true.
- Adds a network hop which nudges up latency. It's unavoidable.
- Complex setup that demands constant attention. You're never really done with it.
- Certificate management balloons into a headache at scale.
Examples in practice
Real-world deployments of Reverse Proxy , where it works and where alternatives win.
Load Balancing at Scale
Nginx acts as a reverse proxy spreading requests across backend pools to ensure no single server crumbles under load. Netflix routes 200M streams this way, keeping it under 100ms latency. Cloudflare uses reverse proxies to shield 20M+ domains, while LinkedIn manages millions of requests in similar fashion.
SSL/TLS Termination
Reverse proxies like HAProxy deal with SSL handshakes, leaving backend servers with just plain HTTP. Cloudflare handles TLS for 20 million sites, Amazon with AWS API Gateway, and Google Cloud Load Balancing does it too, tackling petabytes of traffic.
Web Application Firewall
Reverse proxies pack WAF rules to catch and block bad traffic. ModSecurity on Apache filters out thousands of SQLi and XSS attempts. Akamai uses this to cache and filter for major companies.
Reverse Proxy Caching
Varnish Cache fronts origin servers slinging cached pages in under 1ms. The Guardian dropped backend load by 99% this way. Akamai leverages the same logic for CDN caching for Fortune 500 clients.
Geo-Based Routing
Reverse proxies read client IPs and send requests to the nearest data center. Amazon CloudFront with its 600+ edge locations covers the globe. Google Cloud Load Balancing handles a similar traffic chunk.
API Gateway Proxying
Stripe offers a monolithic reverse proxy endpoint splitting traffic over a sea of internal services. Kong Gateway, with its 100 billion monthly API requests, uses this. Amazon does something similar with AWS API Gateway.
Common misconceptions
Common myths about Reverse Proxy , and what is actually true.
| Myth | Reality |
|---|---|
"A reverse proxy and a VPN do the same thing" | A reverse proxy sits in front of servers to manage inbound traffic, while a VPN encrypts all outbound client traffic through a tunnel. They operate at different layers and solve different problems. |
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