Proxy vs reverse proxy
The same middleman from two ends — one acts for clients reaching out, the other for servers receiving in. Get the direction right and the rest follows.
One concept, two directions
Both are intermediaries that relay traffic. The entire distinction is whose side they’re on — the client’s or the server’s. (Introduced in Chapter 2; here we sharpen it into the comparison interviewers ask for.)
Forward proxy — acts for the client
Sits in front of clients and reaches out to the internet on their behalf. The destination sees the proxy, not the client.
- Hides: the client (its identity/IP) from servers.
- Used for: privacy/anonymity, corporate filtering and logging of outbound traffic, caching popular outbound content, bypassing geo/IP restrictions.
- Configured by: the client (or its network).
Reverse proxy — acts for the server
Sits in front of servers and receives requests from the internet on their behalf. The client thinks it’s talking to one server; many may hide behind it.
- Hides: the servers (their topology/IPs) from clients.
- Used for: load balancing, TLS termination, caching/compression, security and request filtering, serving many backends behind one address.
- Configured by: the server operator.
The side-by-side
| Forward proxy | Reverse proxy | |
|---|---|---|
| Stands in for | The client | The server |
| Hidden party | Client identity | Server topology |
| Sits in front of | A group of clients | A group of servers |
| Typical use | Filtering, anonymity, outbound cache | Load balancing, TLS, caching, security |
| Set up by | Client side | Server side |
The one-liner to remember
- Forward proxy: the client’s agent — the server can’t see who’s really asking.
- Reverse proxy: the server’s agent — the client can’t see who really answered.
The interview cue
You’ll almost always be deploying a reverse proxy (load balancers, gateways, CDNs, and edge caches are all reverse proxies). Mention forward proxies for client-side scenarios — corporate egress, crawlers routing through proxy pools. Stating “reverse proxy — it fronts our servers, terminates TLS, and load-balances” in the right spot shows you know which direction you’re standing in. (Next: how a reverse proxy differs from an API gateway.)