Siteimprove vs Lighthouse

Quote on request

Free and open source

Enterprise annual contracts priced by pages crawled and modules.

Free and open source. You pay in engineering time and CI minutes.

Free browser extension for single-page checks.

Everything, self-hosted

Widely used

Siteimprove · since 2003

Category standard

Google · since 2016

• 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.

• Already installed in every Chrome browser — zero adoption cost.
• Covers performance, accessibility and SEO in one report.
• Lighthouse CI turns scores into enforceable build assertions.

• 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.

• Lab data from a synthetic environment, not what real users experience.
• Scores vary run to run, which makes strict thresholds frustrating.
• Accessibility coverage is the axe-core subset, not a full audit.

Universities, government and large content organisations with legal accessibility obligations.

Every web team as a first, free quality baseline.