What is caching? All about temporary data storage

Caching is the act of intentionally storing a copy of data that you’ve downloaded, so that you don’t need to download it again later. There are a lot of reasons to set up caching, including accessing data faster, maximising available bandwidth, and avoiding wear and tear on networked servers.

What is caching?

The first time you visit a website, your browser downloads the files that you client needs to properly display it and run any scripts on the page. Downloading a fresh copy of this data on every visit would be a waste of time and resources. You would simply slow yourself down while using bandwidth and processing power on tasks that had already been done in the past.

The alternative is to check if there are updates to the page, and only download the newer data, reusing any information that didn’t change since your last visit. That’s called caching. A web browser caches the content of a web page that isn’t likely to change. This means faster page loading every time you visit that site in the future.

Caching uses temporary local storage for all kinds of website elements: HTML, scripts, and images to name a few. When optimising for search engine optimisation (SEO), this is ideal. Google tracks how responsive a site is, as well as its reliability. The slower the sites, the less likely it is to be shown on the first search page.

In short, caching improves both user experience and browser performance.

What other kinds of caching are there?

Browser caching is the first of many methods for speeding up network communication with strategic copies of data. Here are some other ways that this process is used:

Network caching is done on routers and switches so that they don’t need to look up addresses and network paths all the time. Common routing paths and address resolutions are stored in tables, allowing them to make connections nearly instantly. They only check for new settings when the time to live (TTL) setting tells them to see if there’s an updated address.

Mirroring means that a complete copy of the website is stored in strategic locations all around the world, so many users can access a copy in their country.

How does browser caching work?

Browser caching stores website data in a localised cache. There are two ways to do this:

  1. Browser and memory caching stores data right on the client (as long as it has permission to do so). Browser data is either stored in random access memory (RAM) or on a local hard drive or solid-state drive. The next time the user visits that website, the browser loads the data from the cache. If it detects that files have changed on the site, they are downloaded again.
  2. Content delivery networks (CDNs) use methods similar to mirroring, described above. That means requests only need to travel to a local cloud server, even if the main website is hosted on another continent.

Some things can’t be cached due to website settings or browser permissions. If the server includes a tag called ‘no-store’, the browser will never cache that particular data. If the user sets their browser’s preferences to ‘no cache’ (either for one site or as a general rule), they will download the data fresh every time.

The benefits of caching

Caching reduces bandwidth usage and speeds up the loading of web pages. But what else can it do?

Server performance can be drastically improved with the right cache settings. Accessing a drive is much slower than grabbing something that’s already sitting in memory. Less energy used means lower costs, and less of a chance that the server will crash.

The main downside to caching is the security risk involved when it is misconfigured. Improper caching can expose personal information to cyber criminals or put financial or medical information in the hands of someone else if your device is stolen. It can also simply be embarrassing if someone pokes around and sees evidence that you visited certain kinds of websites. Remember to encrypt your devices, use passwords, and clear not only your internet history but your cache if you’re loaning out your device!

How is caching used to enhance SEO?

The settings on your hosting site’s control panel or in your server’s HTTP server suite are used to control what gets cached. Certain utilities can be used to fully optimise your website for better SEO. Average load speeds, the site’s Google ranking, and many other details are used to discover your best caching strategy. Use the right settings and you can even speed up WordPress! Check out some of the popular WordPress caching plugins to learn more about the process.