Website caching explained for business owners

Key takeaways

Website caching means keeping a ready-made copy of something so it does not have to be fetched or built again. It is usually the cheapest large speed gain available to a small business site. Page caching lets the server send a stored page instead of assembling one for each visitor. Browser caching lets a returning visitor's phone reuse files it already has. Both are often switched off or misconfigured.

• Page caching: the server sends a stored copy instead of building the page each time.
• Browser caching: a visitor's device reuses your logo, fonts, styles and scripts.
• Caching is often included with managed hosting and simply needs turning on.
• The main risk is showing out-of-date content, which is avoidable.

What is website caching?

Website caching is the practice of storing copies of pages or files so that later requests can be served from the copy, faster than from the original source.

Think of a café that makes each sandwich to order against one that prepares the popular ones before the lunch rush. The second serves a queue far faster with the same staff. A site without caching makes every page to order, for every visitor.

• How website speed affects customer experience and conversions

What are the main types of caching?

Three types matter for a business site. They work at different points between your server and the customer.

• Page caching: on the server. Finished pages are stored and sent without rebuilding.
• Browser caching: on the visitor's device. Files are kept for the next page or visit.
• CDN caching: on a network of servers. Copies are held close to visitors.
• Object caching: on the server. Database results are remembered, which helps logged-in pages.

• Do you need a CDN for a small business website?
• Time to first byte: is your server the slow part?

How much difference does caching make?

Caching makes the most difference to server response and to every page after the first. With page caching, a server that took two seconds to build a page can reply in a fraction of that. With browser caching, the second page of a visit needs only its own content, because the shared files are already on the phone.

It also lets a modest server handle a surge. Sending a stored copy is far less work than building a page, so the same hosting can serve many more visitors at once.

• Speed between pages: why the second click matters too
• Website slow at busy times? Staying fast under peak traffic

What can go wrong with caching?

Caching goes wrong when a stored copy is shown after the original has changed, or when something personal is stored and shown to the wrong person.

• Stale content: a price or opening time is updated and visitors still see the old one.
• Logged-in pages cached: one customer's details shown to another. This must never happen.
• Baskets and forms cached: items or tokens that do not belong to the visitor.
• Design changes not appearing until the cache is cleared.

• Do speed optimisation plugins work? What they fix and miss

How do you set it up safely?

Use the caching your host or platform provides before adding anything else, and exclude the pages that are personal.

• 1. Ask your host whether page caching is included and on.
• 2. Exclude baskets, checkouts, accounts and form confirmation pages.
• 3. Set long browser cache times for images, fonts, styles and scripts.
• 4. Make sure the cache clears automatically when content is edited.
• 5. Test as a logged-out visitor and as a customer after every change.

• Website hosting for UK small businesses

What does this look like in practice?

A pattern we see on WordPress sites: the hosting plan includes page caching, and it was never switched on, or a caching plugin was installed and left on default settings that exclude most pages. Every visitor waits while the server assembles a page that has not changed in months.

Turning caching on properly, with the right exclusions, is often an hour's work and the largest single improvement in server response. Global Bridge Labs (GBL) checks caching first in any speed review, because it is the cheapest fix there is.

• See client work
• Website Design & Development for UK businesses

Website caching checklist

• Confirm page caching is on for public pages.
• Check personal pages are excluded.
• Check browser cache times on static files.
• Edit a page and confirm the change appears.
• Test a second page view for speed.
• Note how to clear the cache and who can do it.

• The website speed scorecard: score your site in an hour
• How to test website speed the way customers feel it

Next step

If your site builds every page from scratch for every visitor, there is an easy gain waiting. We will check what is cached, what is not and what should be.