Pa11y

Pa11y is a free, open-source toolkit for checking web accessibility, aimed at designers and developers. It suits teams that want to run checks during development and keep them in CI or a daily monitoring workflow. Its breadth is useful, but Pa11y 10 requires a recent Node.js runtime.

Overview

Pa11y covers several stages of web work: the CLI checks an individual page, Pa11y CI checks a list of pages, and Pa11y Dashboard runs daily scans and graphs changes over time. The Webservice supplies JSON data for the dashboard or a custom dashboard-like front end. That makes Pa11y a practical choice for technical teams that want accessibility checks woven into existing workflows, rather than a standalone service for nontechnical users.

It tests websites against WCAG 2.1. The CLI uses WCAG2AA by default and also offers WCAG2A and WCAG2AAA, so teams can select a target appropriate to their work. The repository lists the LGPL-3.0 license.

Key features

Flexible checks and reporting

The CLI loads a page and highlights accessibility issues; it can also test a local HTML file when supplied with an absolute path. Pa11y CI iterates over a page list, which is better suited to repeatable pipeline checks than running pages one at a time. HTML_CodeSniffer is the default test runner, with axe also supported.

Built-in reporters produce human-readable terminal output, CSV, HTML, JSON, or TSV. Configuration through command-line options or JSON and JavaScript files helps teams adapt repeatable checks to their workflow. These options make the tools adaptable, though they also assume users are comfortable configuring developer software.

Monitoring and custom front ends

Dashboard's daily scans and graphs help teams follow improvements and regressions rather than treating each scan as an isolated result. The Webservice can also feed a custom dashboard-like front end. That flexibility is valuable for teams with the capacity to build around JSON data; readers who want a ready-made, nontechnical monitoring service may prefer a different approach.

Pricing

Pa11y open-source tools cost free. The free plan includes the open-source tools, so there is no paid tier to weigh against a feature-limited entry plan. Users do need to account for the technical requirements and setup involved in using them.

Platforms

Pa11y is available for API, Linux, macOS, self-hosted, web, and Windows workflows. The project documents installation requirements for Linux, macOS, and Windows 11. Pa11y 10 requires Node.js 22.13.0 or above and an even-numbered Node.js version, a meaningful prerequisite for anyone setting up the CLI or related tools.

Who it's for

Pa11y is best for developers and teams that want free accessibility checks they can run from the command line, schedule through Dashboard, or integrate into CI/CD. Its CLI, selectable standards, multiple reporters, and API access support different technical workflows. It is a weaker fit for readers seeking a simple standalone checker that avoids Node.js and developer-oriented setup.

Pros and cons

• Pro: A single free toolkit covers one-off page checks, daily scans, CI testing, and JSON data for a custom front end.
• Pro: Multiple reporters, configuration files, and support for both HTML_CodeSniffer and axe give technical teams practical workflow choices.
• Con: Pa11y 10 requires Node.js 22.13.0 or above, which can add setup work or rule it out in environments without that runtime.
• Con: Its command-line, CI, and self-hosted options favor technical users over people looking for a turnkey, nontechnical service.

Alternatives

For a broader selection of tools, browse Website Accessibility Tools or Accessibility Testing Software.

• WAVE is worth considering if you want a freemium alternative with a browser extension as well as API and web access; its API subscription starts at $10 a month, with a 250-credit minimum purchase.
• Octopus Scanner (formerly A11y Scanner) is another free option for macOS and Windows.
• Oobee offers a free scan of a page or whole site and is described by GovTech as open source.
• IBM Equal Access Accessibility Checker is a free, open-source option with browser extensions and CI/CD and automated testing packages.
• Evinced is a paid alternative with a free 14-day site-scanner trial, no credit card requirement, and a limit of up to 50,000 URLs crawled.
• Axe DevTools offers a free extension for checking one page at a time.
• axe-core is a free, open-source accessibility testing engine under the MPL-2.0 license.
• Pope Tech has a free forever plan capped at 25 pages, two users, one website, and one group.

Verdict

Choose Pa11y if you want a free, open-source way to bring web accessibility checks into development, CI, or daily monitoring, and can work with its Node.js requirement. Its main strength is the range of workflows in one toolkit; look elsewhere if you want a less technical, turnkey checker.