Siteimprove vs axe-core
Feature checklists rarely decide anything. What decides it is the pricing metric, who has to write the tests, and which limitation you can live with.
Entry price
Quote on request
Quote onlyFree and open source
Open sourceWhat drives the bill
The metric that actually scales your invoice.
Enterprise annual contracts priced by pages crawled and modules.
Free and open source. You pay in engineering time and CI minutes.
Free tier
Free browser extension for single-page checks.
Everything, self-hosted
Open source
MPL-2.0
Self-hostable
No-code authoring
Languages
Platforms
Fits teams
Adoption
Widely used
Siteimprove · since 2003
Category standard
Deque Systems · since 2015
Strengths
- Scans entire large sites and assigns findings to content owners, not just developers.
- Combines accessibility with SEO and content quality in one governance view.
- Reporting suited to demonstrating compliance progress to executives and regulators.
- Effectively zero false positives, which is why it became the industry default.
- Integrates into any existing test suite in a few lines.
- Free, actively maintained, and aligned with WCAG updates.
Limitations
- Expensive and aimed at organisations with a governance function.
- Weak fit for application testing as opposed to content sites.
- Limited shift-left developer tooling compared to Deque.
- Automated rules detect roughly a third of WCAG issues — the rest need human testing.
- A library, not a workflow: no dashboards, tracking or reporting.
- Only evaluates the DOM state it is given, so dynamic states need explicit test coverage.
Best for
Universities, government and large content organisations with legal accessibility obligations.
Any team that wants accessibility checks inside their existing automated tests.
Pricing last reviewed August 2026 and is indicative only — confirm on each vendor’s own page.