Which tools should an agency use to test client websites?
Split the check into what a tool can measure and what it cannot. Free and low-cost tools cover speed, common accessibility errors and broken links: PageSpeed Insights or Lighthouse, WAVE or axe DevTools, and Screaming Frog's free crawl of up to 500 URLs. A device cloud such as BrowserStack or TestMu AI shows the site on browsers and phones you do not own. None of them tells you whether a stranger can do the client's main task, such as booking or buying. For that, run a task test with a few people or an AI user, and send the client what it found.
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Automated checks: speed, accessibility and links
Speed.PageSpeed Insights tests a URL and shows real-user data from the Chrome User Experience Report next to its lab results. Lighthouse, the open-source tool behind it, also audits accessibility, best practices and SEO.
Accessibility. WAVE runs as a browser extension for Chrome, Firefox and Edge; its API starts with 100 free credits, then costs $0.025 to $0.04 a page. Deque's axe DevTools extension for Chrome is free; its paid plans are sold after a demo or trial.
Links and page titles. Screaming Frog's SEO Spider crawls up to 500 URLs free; a licence costs £199 a year and removes the limit.
These tools check what can be measured from the page. WebAIM, which makes WAVE, says that the absence of detected errors does not mean a page is accessible, so treat a clean report as a floor.
Browsers and phones you do not own
A device cloud opens the client's site on other browsers and devices from your own browser. BrowserStack's Freelancer plan is $12.50 a month billed annually ($19 month to month) for 100 minutes of live testing by one user; its Live Desktop plan, without a minute cap, is $29 a month billed annually. TestMu AI, formerly LambdaTest, has a free plan with live sessions of 2 minutes each, and paid live testing from $15 a month billed annually.
Start with the browsers and phones the client's own analytics shows, if the old site has any. A device cloud shows how the site looks and behaves there; it does not tell you whether visitors understand it.
Can a stranger do the client's main task?
Every check above can pass on a site where nobody finds the booking button. Write down the one task the client's site exists for, such as booking a table, asking for a quote or buying, and watch someone new try it.
Give the task and a starting page, not a tour of the site.
Choose who tries it: a few people who match the client's customers, or an AI user given a persona from the client's brief.
Note where they hesitate and what they expected to find there.
What a task test found that a link check would not
One public run from the Product Hunt board, with its review note. The AI user was asked to decide whether to sign up and looked for the price first. It found only a price in the FAQ, typed the usual pricing address and got a not-found page. A link checker follows the links a site already has, so it does not try an address a visitor guesses.
Every run here used Menso's Purchase intent template: the persona Zainab Salazar, a freelance UX consultant, reads the homepage, the pricing page and the FAQ, decides whether she would buy or sign up, and stops before paying. It is a route-specific diagnostic, not a product-wide score.
AINA
TRACES 64.5/100
Product Hunt week 38 (Sep 14 – 20, 2026), #7 on Product Hunt's board · tested Sep 21, 2026 · one AI user, one run (n=1) · Deep test · 14 of 16 steps · aina-tech.io
Zainab scrolled the candidate page and opened the FAQ. At step 7 she expanded “What does it cost?”, and at step 8 she read the answer: $49 a month, which she took to be the company plan. At step 13 she typed the usual pricing address; at step 14 it returned a not-found page, and she decided not to sign up.
T 4 · R 4 · A 2.5 · C 4 · E 2 · S 2.5 (each out of 5)
Review note: The run mixed the candidate and recruiter purchase contexts; the $49 figure describes the recruiter service, not the free candidate profile.
Made one of these products? Write to support@menso.io and we will correct or remove the example as soon as we can.
What to send the client
Clients sign off on evidence they can open. With Menso, every plan gets a UX report on every run, and Pro and Max can export it as a PDF and make a share link for a replay that opens without signing in. Menso makes no link if it finds a login or secret you gave it in the replay. For a client site behind a login, give the AI user a test account on the credentials card; it signs in with email and password only.
Why accessibility belongs on the list
WebAIM's 2026 check of one million home pages found detectable WCAG 2 failures on 95.9% of them, with an average of 56.1 errors per page. In the EU, the European Accessibility Act covers e-commerce services among others. If you build shops for EU clients, put an accessibility check on the launch list and tell the client what the automated tools cannot check.
Limits of this approach
Automated checks miss problems that need judgment, such as whether a label makes sense or an image description is useful.
An AI user is not your customer. It has no money at stake and no history with your product. Studies of AI-simulated users in conversation tasks report that they can miss friction people feel and make results look more optimistic (Liu et al., Yoon et al.).
One run is one persona on one path (n=1). It shows where that visitor got stuck, not how many of your visitors will.
Prices were read on each tool's own pages on November 5, 2026. Plans change; follow the links for today's.
Questions people ask
What should a client website launch checklist cover?
Five things: speed, accessibility errors, broken links and page titles, how the site looks and works on the browsers and phones the client's customers use, and whether a new visitor can do the main task. Agree with the client before the project which of these you check and which they own, so the launch review has no surprises.
How many people do I need to watch?
For finding problems, a handful. Jakob Nielsen's 2000 article estimates that five users find about 85% of the usability problems in a design, for users who are alike, and recommends several small rounds over one large test. Five people tell you what goes wrong, not how often: for a rate you need far more (Nielsen Norman Group, 2021).
Which of these checks can I do for free?
PageSpeed Insights and Lighthouse, Deque's axe DevTools extension for Chrome, and Screaming Frog's crawl of up to 500 URLs cost nothing. WAVE's API starts with 100 free credits, TestMu AI's free plan gives live sessions of 2 minutes each, and Menso's free plan includes 3 tests a month.
Can an AI user replace testing with the client's customers?
No. It shows one stranger's attempt at the task and where it hesitated, which is useful before launch when there are no visitors yet. It is not the client's customer and has no money at stake. Menso's free plan includes 3 tests a month, enough to try one client task before you decide how to use it.