Proxy
An intermediary component that forwards requests between clients and servers, often adding routing, caching, security, or observability.
Definition
A proxy is an intermediary that sits between a client and a server and forwards requests and responses.
It can be “transparent” (just forwarding) or it can add behavior: routing, load balancing, caching, authentication, rate limiting, TLS termination, or observability.
Where proxies show up
- Reverse proxy in front of an app (common for HTTP services)
- Forward proxy used by clients to reach the internet
- Service mesh sidecars: a proxy running next to each service (sidecar pattern)
Why proxies matter operationally
Proxies can change what your app sees: source IPs, headers, timeouts, retries, compression, and TLS behavior. When something “works locally but not in prod”, a proxy layer is often part of the environment difference.