# Reverse Proxy

![](https://1250864089-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M4Bkp-b8HYQgJF1rkOc%2F-M9pwFBbjVBlN7nxMsRh%2F-M9pzRNbQFe-jR7RAUCF%2Fimage.png?alt=media\&token=67a209fb-48ce-4438-b423-8c3e9e3c4c8a)

Reference: <https://github.com/donnemartin/system-design-primer#reverse-proxy-web-server>

A reverse proxy is a web server that centralizes internal services and provides unified interfaces to the public. Requests from clients are forwarded to a server that can fulfill it before the reverse proxy returns the server's response to the client.

Additional benefits include:

* **Increased security** - Hide information about backend servers, blacklist IPs, limit number of connections per client
* **Increased scalability and flexibility** - Clients only see the reverse proxy's IP, allowing you to scale servers or change their configuration
* **SSL termination** - Decrypt incoming requests and encrypt server responses so backend servers do not have to perform these potentially expensive operations
  * Removes the need to install [X.509 certificates](https://en.wikipedia.org/wiki/X.509) on each server
* **Compression** - Compress server responses
* **Caching** - Return the response for cached requests
* **Static content** - Serve static content directly
  * HTML/CSS/JS
  * Photos
  * Videos
  * Etc

#### Load balancer vs reverse proxy

* Deploying a load balancer is useful when you have multiple servers.  Often, load balancers  route traffic to a set of servers serving the same function.
* Reverse proxies can be useful even with just one web server or application server, opening up the benefits described in the previous section.
* Solutions such as NGINX and HAProxy can support both layer 7 reverse proxying and load balancing.

#### Disadvantage(s): reverse proxy

* Introducing a reverse proxy results in increased complexity.
* A single reverse proxy is a single point of failure, configuring multiple reverse proxies (ie a [failover](https://en.wikipedia.org/wiki/Failover)) further increases complexity.

#### Source(s) and further reading

* [Reverse proxy vs load balancer](https://www.nginx.com/resources/glossary/reverse-proxy-vs-load-balancer/)
* [NGINX architecture](https://www.nginx.com/blog/inside-nginx-how-we-designed-for-performance-scale/)
* [HAProxy architecture guide](http://www.haproxy.org/download/1.2/doc/architecture.txt)
* [Wikipedia](https://en.wikipedia.org/wiki/Reverse_proxy)