Caching refers to storing information locally to speed communication between a client such as a web browser and a server such as a web server. The cache can be located on the client side, the server side, or – as is often the case – both.

Caching is very useful for serving repetitive requests of static or infrequently changing data. On a company’s website, much of the same information gets requested over and over again by different users. By storing that information locally on a server close to the requesting client, it can be delivered to the client considerably faster than if it had to be fetched again from the back-end server.

If the requested information is not available in the cache, it is retrieved from the central storage location, which might be directly connected to the caching server or across the network. When the data arrives at the server, caching algorithms are used to determine if it is likely to be requested again. The data is added to the cache if so, and is also delivered to the client.

To avoid serving outdated (stale) content, the caching server can refresh the cache at a predetermined interval or in response to a certain event such as a user refreshing the web page. This ensures that the user always receives the freshest content available, such as the latest headlines on a news site or the current bid on an auction site.

Caching can also help insulate clients from server outages, by delivering previously cached content until the server is online again.

How Can NGINX Plus Help?

NGINX Plus and NGINX are the best-in-class web server and application delivery solutions used by high-traffic websites such as Dropbox, Netflix, and Zynga. More than 130 million websites worldwide and over 40% of the world’s 10,000 busiest websites use NGINX Plus and NGINX to deliver content quickly and reliably.

  • NGINX Plus was developed specifically to solve the speed limitations inherent in web applications and platforms.
  • NGINX Plus delivers a massively-scalable caching solution to serve up static and infrequently changing content to a wide variety of clients in an optimized and reliable manner.
  • The NGINX Plus caching server can also handle dynamic responses returned from scripting languages using protocols such as FastCGI, SCGI, and uwsgi.
  • The live activity monitoring feature in NGINX Plus reports a broad range of statistics you can use to monitor and measure the utilization and effectiveness of your content caches.