proxy

A proxy is an intermediary that acts on behalf of another party, often coordinating requests to a resource. In computing, a proxy server handles requests from clients seeking resources from other servers, effectively standing in for the client in the communication.

There are several common types of proxies. A forward proxy sits between a client and the wider internet, often used for privacy, access control, or content filtering within an organization. A reverse proxy sits in front of one or more servers, handling incoming requests for load balancing, TLS termination, caching, or security screening. Transparent proxies operate without client configuration, intercepting traffic as it passes through a network. Open proxies are accessible to anyone, while authenticated proxies require credentials. Proxies may implement different protocols, such as HTTP(S) proxies or SOCKS proxies, and may include caching features to improve performance.

Proxies provide several functional benefits. They can mask a client’s IP address, enable access control and content filtering, reduce bandwidth through caching, and balance load across multiple servers. They can also enhance security by isolating backend systems from direct exposure. However, proxies can introduce privacy and trust concerns, since traffic may be logged or altered by the proxy operator. Misconfigurations can lead to data leaks or surveillance, and even legitimate proxies may not provide end-to-end encryption unless used with secure transport.

Other uses of the term include proxy variable in statistics, a proxy vote in governance, and the proxy design pattern in software development. In each case, a proxy serves as a stand-in or surrogate for another entity.