How a reverse proxy works
Visitor → reverse proxy → server A
→ server B
→ server CVisitors connect to the reverse proxy as if it were the website. It decides which server should answer, forwards the request and returns the response. Visitors never talk to the servers behind it directly.
What reverse proxies do
- Load balancing: spread visitors across several servers.
- Caching: serve popular files from memory or from locations near the visitor, as a CDN does.
- Encryption: handle HTTPS so the servers behind it don’t have to.
- Security: filter attacks and unwanted bots before they reach the site.
Reverse proxy vs forward proxy
| Reverse proxy | Forward proxy | |
|---|---|---|
| Sits in front of | Servers | Clients |
| Set up by | The website owner | The user or their company |
| Main job | Balance, cache and protect incoming traffic | Change or control outgoing traffic |
The proxy servers you buy to browse or collect data are forward proxies.
Why it matters when you collect data
The reverse proxy in front of a website is often what rate-limits or challenges automated traffic. A challenge page, a 403 Forbidden or a 429 Too Many Requests usually comes from this layer rather than from the site’s own servers.
FAQ
Is a CDN a reverse proxy?
In effect, yes. A CDN receives requests at servers near each visitor, then serves a cached copy or forwards the request to the website’s own servers. That’s a reverse proxy spread across many locations.
Can I use a reverse proxy to hide my IP?
No. A reverse proxy hides and protects the website’s servers, not its visitors. To change the IP that websites see, you need a forward proxy, such as a residential proxy.
How can I tell a site is behind a reverse proxy?
The response headers often show it, for example Server: cloudflare, a Via header, or cache headers such as X-Cache.