Test accessibility continuously: combine automated checks with manual evaluation, add checks to development workflows, and repeat them whenever content, templates, components, or code changes. Automated tools can surface detectable problems, but a scan or score cannot establish that a site is accessible or conforms to WCAG. For a formal conformance evaluation, use W3C’s WCAG-EM methodology and document the evaluation with its report tool.
How to test a website for accessibility
Start while designing or developing, then revisit accessibility as the site changes. W3C WAI advises: “When developing or redesigning a website or web application, evaluate accessibility early and throughout the development process to identify accessibility problems early, when it is easier to address them.” W3C WAI’s evaluation overview explains the role of evaluation during development.
- Run automated checks early. Use automated testing in a local or acceptance-test workflow where it fits. For example, the UK Department for Work and Pensions identifies axe-core as a tool that can run in acceptance tests. Automated tools differ in what they detect, so do not treat one tool’s output as complete coverage.
- Check pages and components in a browser. Browser-based tools can provide quick feedback on an individual page or component. DWP names axe DevTools and WAVE as options. Use results to identify issues to investigate and fix, not as a conformance verdict.
- Follow up manually. Human evaluation is needed alongside automated findings. For consequential or complex services, DEFRA recommends combining automated tools, manual checks, and professional audits.
- Retest after changes. Recheck affected pages and components when content, templates, shared components, or code change. A fix in a shared component may affect many pages, so include representative uses of that component in your checks.
These methods answer different questions: automated checks find issues that tools can detect; manual evaluation assesses aspects that require human judgment; simulation can help examine aspects of user experience. W3C’s accessibility evaluation tools overview distinguishes these tool types and also describes site-wide tracking.
What automated accessibility testing can—and cannot—tell you
Automated tools are useful for finding detectable issues quickly and repeatedly, especially during development. Their results depend on the tool, the content and states tested, and the guidelines and checks it covers. A clean report means only that the tool did not report issues in the checks it ran; it does not prove that every user can use the site or that the site conforms to WCAG.
#1 Best Overall
Do not use a single score as a substitute for evaluation. Investigate findings, perform manual checks, and choose a broader evaluation when the service’s complexity or consequences warrant it. The available sources do not establish one universal percentage of accessibility problems that scanners detect, so avoid treating any such percentage as a dependable general benchmark.
How to choose accessibility testing tools
Choose tools based on the work you need to do rather than looking for one universally best checker. W3C’s tool directory and selection guidance describe tools with different combinations of capabilities.
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- Method: Decide whether you need automated detection, guidance for manual evaluation, or simulation of aspects of user experience.
- Scope: Check whether the tool handles a single page, a sample, an entire site or app, and restricted or password-protected content if those pages matter to your evaluation.
- Coverage: Confirm which standards or guidelines the tool covers and what platform or browser support it provides.
- Output: Consider whether the team needs issue details, reports, scores, or step-by-step evaluation guidance.
- Workflow fit: An extension may suit individual page checks; a test integration may fit code changes; a recurring service may suit site-wide reporting.
For examples, W3C lists axe DevTools among evaluation tools and axe Monitor as an enterprise monitoring and reporting platform. WAVE describes page evaluation as well as APIs and subscription offerings for collecting test data across many pages. These are examples of different approaches, not endorsements or a ranking; capabilities and offerings can change.
When to use WCAG-EM for a conformance evaluation
Routine scans and development checks are not the same as a formal WCAG conformance evaluation. W3C’s Website Accessibility Conformance Evaluation Methodology (WCAG-EM) is a methodology for determining WCAG conformance. Use the method when you need a structured evaluation, and document it with the W3C WCAG-EM Report Tool. The report tool supports documenting an evaluation; it does not turn an automated scan into a conformance finding by itself.
How to monitor accessibility after launch
Repeat checks when content, templates, components, or code change. A team with frequent releases can tie checks to release or acceptance workflows; a site with many pages may need a sample-based or whole-site approach suited to its scale and risk. W3C notes that some organizations need fully automated whole-site tracking, while its tool directory includes tools with different scopes.
There is no universal monitoring cadence established by the cited guidance. Set a schedule in relation to how often the site changes, how large it is, and the impact of an accessibility failure. Also trigger checks after significant changes rather than relying only on a calendar. Whole-site monitoring can help make repeated checks practical, but it does not replace manual evaluation or an appropriately scoped conformance assessment.
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Capture visual evidence while testing
Screenshots can help document how a page or component appeared during a test, but an image is evidence of appearance, not proof of accessibility. Record the page and state being examined and pair visual evidence with the relevant automated findings and manual evaluation.
For capturing a screenshot by API, ScreenshotNeo is a website screenshot API and MCP server for developers. A screenshot can preserve a visual state for review, but it does not itself test WCAG conformance or replace accessibility testing.
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One GET request can capture a URL. See the ScreenshotNeo API documentation for parameters and response details.
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curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://stripe.com -o shot.webpScreenshotNeo removes cookie banners, newsletter popups, and chat widgets before capture; each step can be turned off. Bot checks, blank pages, and failed loads are not billed. An MCP server lets AI agents take screenshots. The free plan includes 1,000 screenshots a month with no card, and paid plans start at $5 for 3,000. Sign up for 1,000 free screenshots a month, with no card required.
Troubleshooting accessibility checks
- The scan reports no issues, but users still encounter barriers: Automated checks cover detectable conditions, not every aspect of accessibility. Add manual evaluation and, where appropriate, an expert audit.
- A finding appears only on certain pages or states: Confirm the relevant content, component, or interaction is present in the test. Check the affected page state manually and include representative cases in future runs.
- The team cannot check every page by hand: Use a combination of representative page checks and recurring whole-site tracking where useful. Select scope according to site size and risk, and keep manual evaluation in the process.
- Reports from different tools disagree: Tools can differ in their checks and coverage. Review each finding, the tool’s documented scope, and the relevant page rather than assuming one output settles the question.
- You need to state whether the site conforms to WCAG: A scanner result is not that determination. Follow WCAG-EM and document the evaluation with W3C’s report tool.
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