Forward vs Reverse Proxy: What's the Difference?

Both a forward proxy and a reverse proxy are intermediaries that relay traffic, but they represent different parties and sit on opposite ends of the connection.

A forward proxy sits in front of clients and represents them to the wider internet. When you route your browser or script through it, the destination server sees the proxy's address instead of yours — that is how a forward proxy hides the client's origin IP. This is the everyday meaning of "proxy", and it is exactly what s4m's SOCKS5 and HTTP proxies are: forward proxies you point your traffic through.

A reverse proxy sits in front of servers and represents them to clients. When you visit a big website, you often connect to a reverse proxy that then forwards your request to one of many backend servers. The client usually has no idea it exists. It protects and fronts the origin servers rather than the client — the mirror image of a forward proxy. For the full picture see our reverse proxy guide.

Forward proxy — serves the client:

• Hiding the client's IP so the destination sees the proxy (privacy, web scraping, ad and SERP verification).
• Access control and content filtering on a corporate or school network (all outbound traffic passes through it).
• Caching outbound requests and bypassing geo-restrictions.

Reverse proxy — serves the server:

• Load balancing across multiple backend servers.
• TLS/SSL termination, so backends do not each handle encryption.
• Caching and compression (CDNs are giant reverse proxies) and hiding the origin server's real IP.
• Security: a WAF, DDoS protection and a single controlled entry point in front of the application.

Common examples: Nginx, HAProxy, Traefik and Cloudflare act as reverse proxies; Squid and the SOCKS5/HTTP proxies you configure in a client act as forward proxies. The same software can sometimes do both, but the role is defined by which side it fronts. A useful way to see the symmetry: a forward proxy hides many clients behind one outward-facing address, so servers cannot tell the individual users apart; a reverse proxy hides many servers behind one inward-facing address, so clients cannot tell the individual backends apart. In both cases the intermediary is the single visible point, and the thing it protects — the crowd of clients, or the pool of servers — stays out of direct view.

Rule of thumb: if it protects the person making the request, it is a forward proxy; if it protects the service receiving the request, it is a reverse proxy.