October 28, 2026
Skip the cross-browser and accessibility pass before a London launch and you will regret it the first week a customer cannot finish checkout on their phone.
Website testing services in London should cover five things before go-live: cross-browser and device checks, accessibility against WCAG 2.2 AA, performance against Core Web Vitals, functional checks of forms, payments and integrations, and a technical SEO pass. You can buy that from a local agency or outsource it to a remote QA team that works UK hours. What decides the result is the test scope and the evidence you get back, not the postcode of the people doing it.
Astaqc and TestInspector.ai. Astaqc provides experienced QA talent to London clients, working UK hours on website, web app and e-commerce releases. TestInspector.ai can create, run and monitor your tests without any human intervention: humans do the testing while the AI monitors the regressions. TestInspector.ai starts at USD 349.
A website test is not one activity. It is a set of checks, and each one catches a different kind of failure. A useful proposal names every check, the pages or flows it applies to, and the evidence you get at the end.
| Check | What it catches | Evidence you should get |
|---|---|---|
| Functional | Broken forms, failed payments, wrong redirects, dead links, CMS content that breaks layouts | Test cases with pass or fail per flow, defects with steps to reproduce |
| Cross-browser and device | Layout and behaviour differences between Chrome, Safari, Firefox and Edge, on desktop and mobile | A browser and device matrix with results per cell, screenshots of failures |
| Accessibility | Keyboard traps, missing labels, poor contrast, content that screen readers cannot follow | WCAG 2.2 AA findings by success criterion, with severity and a fix note |
| Performance | Slow pages, layout shift, heavy scripts, poor responsiveness | Core Web Vitals per key template, lab and field data where available |
| Technical SEO | Missing titles, wrong canonicals, blocked pages, broken redirects, sitemap errors | A crawl report with each issue and the affected URLs |
| Privacy and consent | Trackers that fire before consent, a cookie banner that does not record choices | A record of which tags fire before and after consent |
Our website testing service covers all six. If your site is closer to an application, with logins, dashboards and roles, the web app testing scope is the better fit.
Cross-browser testing is where most launch bugs hide, because the team that built the site usually tested it in one browser on one laptop. The fix is a written matrix agreed before testing starts.
Our compatibility testing service builds and runs this matrix. For repeat runs, TestInspector.ai runs the same flows on Chrome, Firefox, Edge and Safari and compares screenshots against an approved baseline, so a layout regression shows up as a visual diff rather than a customer complaint.
Accessibility is the check UK teams most often leave until last, and the one with the clearest legal context. It is also the one that helps the most real users.
A good accessibility pass combines automated scanning with manual checks. Scanners find missing alt text, contrast failures and unlabelled fields quickly. Only a person with a keyboard and a screen reader finds a modal you cannot close, a carousel that steals focus, or an error message that is never announced.
Our post on 508 compliance testing for web applications covers the overlap between Section 508 and WCAG, which matters if you also sell to US public bodies. TestInspector.ai runs axe-core accessibility assertions with severity levels inside regular test runs, so accessibility regressions are caught between audits.
Performance testing for a website is mostly about three Core Web Vitals, measured at the 75th percentile of real visits.
| Metric | What it measures | Google's 'good' threshold |
|---|---|---|
| Largest Contentful Paint (LCP) | How fast the main content appears | 2.5 seconds or less |
| Interaction to Next Paint (INP) | How quickly the page responds to taps, clicks and key presses | 200 milliseconds or less |
| Cumulative Layout Shift (CLS) | How much the layout jumps while loading | 0.1 or less |
Test each page template, not just the home page: product pages, category pages, articles and checkout often fail for different reasons. Lab tools such as Lighthouse tell you why a page is slow; field data from real users tells you whether it matters.
See our guide to frontend performance testing and Core Web Vitals for how to set budgets per template and fail a build when one is exceeded. If you expect traffic spikes from a campaign or a sale, add load testing on top.
Outsourced website testing comes in three shapes, and each suits a different stage of a site's life.
| Model | Best for | What to agree upfront |
|---|---|---|
| Pre-launch audit | A new site or a redesign going live on a fixed date | Scope of pages and flows, browser and device matrix, accessibility level, report format |
| Release-based testing | Sites that ship changes every week or every sprint | Turnaround per release, regression checklist, how defects are logged |
| Ongoing QA team | Large sites, e-commerce, or sites with frequent content and feature changes | Named testers, hours of cover, automation plan for the regression set |
Cost is driven by scope, not by the word "website". The main drivers are the number of templates and flows, the size of the browser and device matrix, the accessibility level, whether payments and integrations need test accounts, and how often you release. Quotes are only comparable when they cover the same matrix and the same evidence.
Our software testing cost and pricing guide explains the common pricing models. If you are weighing a London agency against a remote team, read how to outsource software testing first, and our list of software testing companies in London for a wider view of the market.
Use this list in the last week before a London launch. Each line should have an owner and a result.
If any line fails, decide before launch whether it blocks go-live or goes on a dated fix list. Writing that decision down is part of the test.
The best ones agree a written browser and device matrix, test accessibility against WCAG 2.2 AA with manual checks as well as scanners, measure Core Web Vitals per template and give you evidence for every check. They can be based in London or work remotely on UK hours; ask to see a sample report before you choose.
Outsource when you are launching or redesigning on a fixed date, when you lack testers who know accessibility and cross-browser work, or when your developers are testing their own code. Keep it in-house when testing is already a regular, staffed part of your release process.
It depends on the number of templates and flows, the browser and device matrix, the accessibility level, payment and integration testing and how often you release. Ask each provider to quote the same scope, and compare the evidence they deliver rather than the day rate alone.
Public sector bodies have specific accessibility regulations, and private sector service providers have duties under the Equality Act 2010. Most organisations treat WCAG 2.2 AA as the working standard. Take legal advice for your specific situation.
If you have a London launch or redesign coming up, we can agree a browser matrix, an accessibility scope and a report format with you before testing starts.
Astaqc's head office is in Mumbai, India. Email contact@astaqc.com or call or WhatsApp +91 98921 33545, 9am to 6pm IST, or use the contact form.
If you want automated regression coverage without building a framework, see TestInspector.ai. TestInspector.ai starts at USD 349.
What decides the result is the test scope and the evidence you get back, not the postcode of the people doing it.
October 28, 2026
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