reverse proxy
/ree-VERS PROK-see/ · noun · Development · Origin: 1996
Definitions
A server that sits in front of one or more backend servers and forwards client requests to them, appearing to the client as the origin server. Reverse proxies provide load balancing, SSL termination, caching, compression, and security benefits. Nginx and Cloudflare are the most common reverse proxies on the modern web.
In plain English: A server that sits between users and your actual web servers, forwarding requests while providing security, speed, and load distribution.
Example: The reverse proxy handles TLS termination and rate limiting so our application servers only deal with plain HTTP and business logic.
Etymology
- 1995
- The Apache HTTP Server added mod_proxy, enabling reverse proxying. The concept distinguished 'forward proxies' (client-side) from 'reverse proxies' (server-side).
- 1996
- The term 'reverse proxy' entered common usage as web architectures grew more complex. Reverse proxies provided load balancing, SSL termination, and caching at the server edge.
- 2004
- Nginx was released, designed from the ground up as a high-performance reverse proxy and web server. It became the dominant reverse proxy for modern web stacks.
- 2010s
- Cloud-native architectures made reverse proxies ubiquitous. Tools like Traefik, Envoy, and AWS ALB automated service discovery and routing in microservice environments.
Origin Story
The Server That Stands Between You and the Internet
A reverse proxy is a server that sits in front of one or more backend servers, intercepting requests from clients and forwarding them to the appropriate backend. The concept emerged in the mid-1990s as web traffic grew beyond what a single server could handle. The Apache HTTP Server, first released in 1995, was among the earliest to support reverse proxy functionality through its mod_proxy module. The term 'reverse proxy' distinguishes it from a 'forward proxy,' which sits in front of clients and forwards their requests outward. A reverse proxy sits in front of servers and handles incoming requests. This seemingly simple inversion unlocks powerful capabilities: load balancing across multiple backend servers, SSL termination (handling encryption at the proxy rather than the backend), caching, compression, and protection against direct attacks on backend infrastructure. The Squid proxy server (first released 1996) and later Nginx (created by Igor Sysoev in 2004) became the dominant reverse proxy implementations. Sysoev created Nginx specifically to solve the 'C10K problem' of handling 10,000 simultaneous connections, which existing servers like Apache struggled with. Today, nearly every large web application sits behind a reverse proxy or content delivery network that functions as one.
Context: Apache HTTP Server and early web architecture, mid-1990s
Fun fact: Igor Sysoev started building Nginx in 2002 while working as a system administrator at the Russian internet portal Rambler. He released it in 2004, and by 2023, Nginx was the most-used web server in the world, surpassing Apache.