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Buyer's guide · Updated September 2026

Best WCAG accessibility checkers for web agencies (2026)

WAVE, axe DevTools, Lighthouse, Pa11y, Siteimprove, Silktide and QA Proof — what each one is good at, where it falls short, and which to pick for the way your agency works.

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Disclosure: we make QA Proof, one of the tools in this guide. We've tried to be fair — where another tool is the better choice, we say so.

TL;DR

There is no single best WCAG checker for web agencies — most use two or three. WAVE (WebAIM) and axe DevTools (Deque) are the best free browser tools for hands-on inspection of a page; axe-core is the standard for developers testing in CI; Lighthouse is the quickest built-in check in Chrome; Pa11y is a free, self-hosted option for scripting checks; Siteimprove and Silktide suit larger organisations that need site-wide crawling, with quote-based pricing. QA Proof suits small and mid-sized agencies that want hosted, no-install WCAG audits of client pages with a 0–100 score, a CSS selector and code snippet per issue and PDF reports, with a free no-signup checker and paid plans from $29/month. Automated tools only catch part of WCAG issues, so pair any of them with manual keyboard and screen-reader testing.

Accessibility checkers compared at a glance

Pricing models and capabilities as publicly described by each vendor at the time of writing. Check each vendor's site for current plans.

Tool Type Best for Cost Many pages / sites Client-ready reports
WAVE (WebAIM) Browser extension and online tool Hands-on inspection of one page, learning WCAG Free; paid WAVE API for bulk testing One page at a time in the free tools No built-in export in the extension
axe DevTools (Deque) DevTools extension plus the open-source axe-core engine Developers, automated tests and CI axe-core free; extension free version plus paid plans Automated tests you write; enterprise site monitoring is a separate Deque product Developer-oriented
Lighthouse (Google) Built into Chrome DevTools; also a CLI Quick spot checks next to performance and SEO Free, open source One page per run; scriptable with Lighthouse CI HTML/JSON report with a 0–100 accessibility score
Pa11y Open-source command-line tool, Pa11y CI and Pa11y Dashboard Developers scripting checks over lists of URLs Free, self-hosted Yes, if you script and host it Basic; you build your own reporting
Siteimprove Enterprise SaaS platform Large organisations: site-wide crawling and governance, alongside SEO and analytics Enterprise, quote-based Yes — crawls whole sites Yes — dashboards and reports
Silktide SaaS platform, plus a free browser extension Organisations that want site-wide accessibility monitoring Platform pricing on request Yes — crawls whole sites Yes — dashboards and reports
QA Proof Hosted SaaS, WordPress plugin and REST API Small and mid-sized agencies auditing client pages without installing anything Free no-signup checker; paid plans from $29/month Per-page audits on demand; script many URLs via the API Yes — 0–100 score, AI summary and PDF report

The tools, one by one

WAVE by WebAIM

The free evaluation tool from WebAIM, available as browser extensions for Chrome, Firefox and Edge and as an online tool.

Strengths

  • Free, and trusted by accessibility professionals
  • Shows issues in context, directly on the page, with structure, reading-order and contrast views
  • Extension evaluates the page as rendered in your browser, so it works behind logins and on localhost

Limits

  • One page at a time; no saved history in the free tools
  • No overall score and no client report built into the extension
  • Interpreting results takes some accessibility knowledge

WAVE vs QA Proof →

axe DevTools by Deque

A DevTools extension built on axe-core, the open-source rule engine used widely across the industry — including inside Lighthouse.

Strengths

  • The de facto standard engine for automated accessibility testing
  • axe-core runs in test frameworks such as Playwright, Cypress, Selenium and Jest, so checks can gate pull requests
  • Paid plans add guided manual tests for criteria automation cannot judge

Limits

  • Made for developers: output lives in DevTools and test logs
  • Client-friendly reporting and site-wide monitoring are separate paid Deque products

axe DevTools vs QA Proof →

Google Lighthouse

Built into Chrome DevTools and PageSpeed Insights. Its accessibility category runs a subset of axe-core rules and gives a weighted score.

Strengths

  • Already in every Chrome browser — zero setup
  • One report covers accessibility, performance, SEO and best practices
  • Scriptable in CI with Lighthouse CI

Limits

  • Checks fewer accessibility rules than a dedicated tool
  • A score of 100 is easy to misread as "accessible"

Pa11y

A free, open-source command-line accessibility tester, with Pa11y CI for pipelines and Pa11y Dashboard for a simple web view.

Strengths

  • Free and fully under your control
  • Easy to run over a list of URLs in scripts or CI

Limits

  • You install, host and maintain it
  • Reporting for clients is up to you

Siteimprove

An enterprise digital governance platform that crawls entire websites and combines accessibility with content quality, SEO and analytics.

Strengths

  • Site-wide crawling and ongoing monitoring at large scale
  • Governance features for organisations with many editors and sites

Limits

  • Enterprise, quote-based pricing — usually out of reach for small agencies reselling to many small clients
  • More platform than most agency projects need

Silktide

A website quality and accessibility monitoring platform that crawls whole sites, plus a free browser extension for checking pages.

Strengths

  • Site-wide accessibility monitoring and reporting
  • Free browser extension for quick page checks

Limits

  • Platform pricing is not published — you need to talk to sales
  • Aimed at organisations more than per-client agency work

QA Proof

Our tool. A hosted QA platform whose accessibility audit checks WCAG 2.1 at Level A, AA or AAA on any public page — from the dashboard, a free WordPress plugin or the REST API.

Strengths

  • Nothing to install; a free checker runs one page with no signup
  • Every issue has a severity, WCAG criterion, CSS selector and HTML snippet, with markers on a full-page screenshot
  • 0–100 score, AI summary and a PDF report you can email to a client
  • Visual regression monitoring and Figma design checks in the same account

Limits

  • Public pages only — no pages behind a login or on localhost
  • Audits run per page on demand; no site-wide crawler, and scheduled monitors cover visual regression, not accessibility
  • No CI integration and no guided manual testing

Which to pick when

If… Pick
You need to understand and fix one page by hand WAVE or axe DevTools (both free)
Developers want accessibility checks to run on every pull request axe-core in your test suite, or Pa11y CI
You want a quick score alongside performance and SEO Lighthouse
A large organisation needs crawling and governance across thousands of pages Siteimprove or Silktide
An agency needs client-ready audits of many sites, run by non-developers, without installing anything QA Proof
You manage WordPress sites and want audits inside wp-admin QA Proof’s free WordPress plugin
You need a formal conformance report (for example an ACR/VPAT) A manual audit by accessibility specialists — tools support it but can’t replace it

A common agency setup: WAVE or axe DevTools while fixing, axe-core in CI for projects you build, and a hosted audit with reports for the sites you maintain for clients.

Automated checkers only catch part of the problem

Every tool in this guide tests what a machine can measure: colour contrast, missing labels and alt attributes, invalid ARIA, heading and landmark structure. Many WCAG success criteria need a person — whether alt text is meaningful, whether focus order makes sense, whether a date picker works with a keyboard and a screen reader. Use automated audits to clear the measurable issues quickly, then test key journeys manually. Be wary of any tool or overlay widget that promises automatic compliance.

Why agencies are being asked about accessibility now

European Union. The European Accessibility Act (Directive (EU) 2019/882) has applied since 28 June 2025. It covers a defined set of products and services sold to consumers in the EU — including e-commerce, consumer banking, e-books and passenger transport services — and applies to businesses outside the EU that sell into it. Microenterprises providing services are exempt. The harmonised standard EN 301 549 references WCAG 2.1 Level AA for web content.

United Kingdom. The Equality Act 2010 requires service providers to make reasonable adjustments for disabled people, which is widely understood to include websites and apps. Public sector websites also fall under the Public Sector Bodies Accessibility Regulations 2018.

United States. Website accessibility lawsuits under the Americans with Disabilities Act are common, and WCAG 2.1 AA is the usual benchmark used to judge a site.

This is a general overview, not legal advice.

Common questions

For inspecting a page by hand, WAVE (WebAIM) and the free version of axe DevTools (Deque) are the most widely used free browser tools. Lighthouse is built into Chrome DevTools and gives a quick accessibility score. Pa11y is a free, open-source command-line option for developers. If you want to check a public page without installing anything, QA Proof’s free accessibility checker runs an automated WCAG 2.1 AA check with no signup.
No. Automated tools reliably find measurable issues — colour contrast, missing labels, invalid ARIA, heading structure — but many WCAG success criteria need human judgement, such as whether alt text is meaningful, whether content makes sense in reading order, and whether complex widgets work with a keyboard and screen reader. A clean automated result is a good start, not proof of conformance. Pair automated audits with manual testing, and use specialist auditors when you need a formal conformance report.
Five things matter most for agencies: it works across many client sites without per-site setup; each issue comes with enough detail for a developer to fix it (WCAG criterion, element selector, code); results are saved so you can show progress; there is a report a non-technical client can read; and the pricing fits the number of sites you manage. Browser extensions are free but leave reporting to you, while enterprise platforms cover whole sites at enterprise prices.
No. Overlay or toolbar widgets that claim to fix accessibility automatically do not repair the underlying code, and they are widely criticised by accessibility practitioners and disabled users. In 2025 the US Federal Trade Commission took action against an overlay vendor over its claims that its AI tool could make websites compliant. Fixing the site itself is the reliable route.
WCAG 2.1 Level AA is the benchmark most laws and standards point to, including EN 301 549, the harmonised standard used for the European Accessibility Act. WCAG 2.2 (a W3C Recommendation since October 2023) adds criteria such as minimum target size and focus not obscured, so testing 2.2 AA is sensible for new work. QA Proof audits against WCAG 2.1 at Level A, AA or AAA and also flags touch targets that are too small under WCAG 2.2.
Run an audit before launch, after redesigns and theme or plugin updates, and whenever important templates or content change — plus a regular review, for example quarterly, because content editors and third-party scripts introduce new issues over time. Keeping past results makes it easy to show a client that issues are going down.

Detailed comparisons: WAVE vs QA Proof and axe DevTools vs QA Proof. More on the QA Proof accessibility audit.

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