What is website testing, and why is it important?
Website testing (sometimes called web testing or site testing) is a series of checks that make sure a website works as it should on every browser, device and type of user. It covers how fast the site loads, whether every link, button and form works, how easy it is to use, and whether search engines can find and read it. From speed and usability to browser compatibility and SEO, it’s how you identify and fix issues before they affect your users or your site’s performance.
Whether you’re launching a brand new site or making improvements to an existing one, testing is a crucial part of any website development project, and it’s built into every web design project we deliver. Testing a website covers both technical and user-facing elements. On the technical side, it ensures everything loads properly, functions as expected and integrates with third-party tools or platforms. On the user-facing side, it makes sure people can easily navigate the site, interact with content and complete key actions like filling in a form or completing a purchase.
In short, the testing of a website is how you make sure it is doing what it’s supposed to, reliably, quickly and smoothly, for everyone who visits.
Launching or refreshing a website is a big milestone. But what happens between finishing the build and going live often makes the biggest difference to how well it performs. That’s where testing comes in.
In this guide we’ll explain what website testing covers, why it matters, how to test a website, and the checklist we work through before every launch.
Why is website testing important?
Your website is often the first contact people have with your business. If something doesn’t work, whether it’s a broken form, a slow page or a confusing menu, most visitors won’t tell you. They’ll just leave. And if the problem is an enquiry form, you may never know they were there.
The main reasons to test your website are that it helps you:
- catch bugs and design flaws before customers do
- make pages load faster
- give mobile and desktop users an equally good experience
- spot SEO problems that could hold back your search traffic
- remove friction, so more visitors become enquiries or sales
Testing isn’t only for launch day. Plugin updates, new content and browser updates can all break things, so regular testing is worth building into how you look after your site, not treating it as a one-off before launch.
What does website testing cover?
Functional testing
Functional testing, sometimes called website functionality testing, asks one question: does everything do what it’s supposed to? This means clicking every link and button, submitting every form, and running through every journey that matters: making an enquiry, booking a call, and for online shops, everything from product pages to checkout. It also means checking where form submissions actually go. A form that “works” but emails an inbox nobody reads is still broken.
Browser and platform testing
Not everyone uses the same browser or device. Browser testing checks your site works properly in Chrome, Safari, Edge and Firefox. Platform testing checks it on phones, tablets and laptops of different screen sizes.
Cross-browser and cross-platform testing typically checks for:
- layout problems or broken elements
- text or images that don’t fit smaller screens
- menus, buttons and forms that behave differently on different devices
These issues are easy to miss when you only check the site on your own laptop, and they can quietly send visitors to a competitor.
Website speed testing
If a page takes too long to load, people won’t wait. Speed also affects your Google rankings through Core Web Vitals, which measure how fast the main content appears, how quickly the page responds, and how stable the layout is.
Free tools like Google PageSpeed Insights and GTmetrix show how fast your pages load and what’s slowing them down. Common causes include:
- large, uncompressed images
- slow hosting or server response times
- unnecessary scripts, plugins and code
User experience (UX) testing
A site can work perfectly and still be hard to use. UX testing looks at how real people move through your pages: what they click, how far they scroll and where they give up. Useful methods include:
- heatmaps and session recordings
- A/B testing, where a change to a layout or wording is shown to a small number of visitors before it’s rolled out to everyone
- watching a few customers try to complete a task, then asking what confused them
The goal is to remove friction between landing on the site and getting in touch.
Accessibility testing
Accessibility testing checks that people with disabilities can use your site. That includes people using screen readers or keyboards instead of a mouse, and people who need strong colour contrast. It’s the right thing to do, it widens your audience, and it often improves the site for everyone. Our guide to web accessibility fundamentals covers the basics.
SEO testing
A beautiful, working site won’t bring in business if nobody can find it. SEO testing checks that:
- every page has a unique title tag, meta description and one H1
- internal links and structured data are in place
- the site is mobile-friendly and passes Core Web Vitals
- Google can crawl and index the pages that matter (check this in Google Search Console)
- old URLs redirect properly when a site is rebuilt, so you don’t lose existing rankings
That last point catches out a lot of redesigns. We cover the rest in our guide to SEO websites.
Security testing
Check that the whole site runs on HTTPS, that the CMS and plugins are up to date, and that forms are protected against spam. For ecommerce sites, test that payments are handled securely from basket to confirmation.
How do you test a website? The website testing process
If you’re wondering how to do website testing in practice, this is the process we follow:
- Agree what success looks like. List the journeys that matter most, such as “request a quote” or “buy a product”.
- Test on a staging site first. Never test on the live site if you can avoid it.
- Run functional tests. Click everything, submit every form and confirm where each one lands.
- Test across browsers and devices, starting with the ones your visitors use most. GA4 shows you which.
- Run speed, accessibility and SEO checks using PageSpeed Insights and Search Console.
- Get fresh eyes on it. Someone who hasn’t seen the site will spot problems the team no longer notices.
- Fix, retest and launch. Then test the live site again straight after launch.
- Keep testing. Recheck after major updates, and review analytics for pages where visitors drop off.
Website testing checklist before launch
- Every page loads, with no broken links or missing images
- Every form submits, sends a confirmation, and reaches the right inbox
- Phone numbers and email addresses are clickable on mobile
- The site works in Chrome, Safari, Edge and Firefox, on phone, tablet and desktop
- Key pages pass Core Web Vitals in PageSpeed Insights
- Every page has a unique title tag, meta description and one H1
- Old URLs redirect to their new equivalents
- An XML sitemap is submitted in Google Search Console
- GA4 is tracking enquiries, calls and form fills as key events
- The site runs on HTTPS, with up-to-date plugins and spam protection on forms
- The cookie banner and privacy policy are in place
Website testing at TLH
We build our websites on insight, not guesswork, so testing is part of every web design and web development project we deliver from our office in Preston. Before a site goes live, we work through the checklist above, then retest the live site after launch.
If your current site is slow, losing enquiries, or you’re not sure it works properly on every device, we can test it for you. We’ll tell you what we find, and what we’d fix first. If the problem is that visitors arrive but don’t get in touch, read our guide to improving your website’s conversion rate.
About to launch a new site, or worried about your current one? Tell us what you’re working on or call us on 01772 319 505, and we’ll make sure it works, for every user, every time.
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