axe vs Pa11y vs Lighthouse vs Certvo: An Honest Head-to-Head (2026)

There are a lot of accessibility scanning tools. axe-core, Pa11y, Lighthouse, and Certvo are the four I get asked about most often, so I ran them all against the same set of sites and put together an honest comparison. “Honest” means I work at Certvo and I am still going to tell you when the other tools do things better.

Feature Matrix

Performance Benchmarks

These numbers are from running each tool against a 50-page e-commerce site (authenticated, so Lighthouse had to be run manually per page):

A word on issue counts: more issues does not automatically mean better. Some tools report one issue per violation (Certvo, axe-core); others group similar issues (Lighthouse). What matters is whether the reported issues are real and actionable.

Honest Verdicts: When to Use Which

Use axe-core when:

• You want to embed accessibility testing directly in your component tests (axe-core integrates with Jest, Cypress, Playwright, Storybook)
• You need CI/CD gates that block PRs on accessibility regressions
• You want the most battle-tested, widely-audited rule set — axe-core's rules have been refined by thousands of contributors over many years
• Your team is developer-first and comfortable with tooling

See our full axe-core comparison for more detail.

Use Pa11y when:

• You need to batch-scan hundreds of URLs from the command line
• You want a lightweight, scriptable tool that outputs JSON for custom reporting
• You are running scheduled scans on a server without a full CI pipeline

See our Pa11y comparison for specifics.

Use Lighthouse when:

• You want a quick, ad-hoc check on a single page without installing anything
• You need performance + accessibility + SEO in a single report for a client presentation
• You are doing initial due diligence on a site you have never audited before

Its accessibility score is useful as a rough health indicator, not as a compliance determination.

Use Certvo when:

• You want to scan AND get production-ready code fixes without writing them yourself
• You need to generate a VPAT for procurement conversations
• You need continuous monitoring with alerts when new deployments break accessibility
• You need to prove compliance posture to a client, auditor, or legal team with timestamped reports
• Your team wants accessibility to be an MCP-accessible service (agents can call the scan API directly)

The Bottom Line

These tools are not mutually exclusive. A mature accessibility practice uses axe-core in CI to prevent regressions, Certvo for full-site monitoring and fix generation, and Lighthouse for quick ad-hoc checks. The mistake is using only one tool and believing it gives you the full picture.

Start with a free Certvo scan to see where your site stands — then decide which ongoing tooling makes sense for your workflow.