Lighthouse vs Siteimprove

Free and open source

Quote on request

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

Enterprise annual contracts priced by pages crawled and modules.

Everything, self-hosted

Free browser extension for single-page checks.

Category standard

Google · since 2016

Widely used

Siteimprove · since 2003

• 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.

• 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.

• 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.

• 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.

Every web team as a first, free quality baseline.

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