Compare software

The Nu Html Checker vs HTML-validate: catalog facts
The Nu Html Checker	HTML-validate
Free Free and open source under the MIT license.	Free Free to use, with the source code published on GitLab.
Windows, macOS, Linux, Self-hosted, Command line	Command line
Checks HTML, CSS, and SVG Can run in scripts or as a self-hosted HTTP service	Validates entirely offline, so no markup is uploaded Handles HTML fragments inside Vue.js and AngularJS components
The portable JAR and WAR packages require Java 17 or later Deploying the WAR package requires a servlet container such as Tomcat	Command-line and tooling oriented, with no graphical interface Checks markup only, not CSS or accessibility in a browser
Downloadable app, Self-hosted	Downloadable app
Open source	Closed source
License: MIT	License not stated
Not stated if an account is needed	No account needed
Not stated if it works offline	Works offline
Official website Full listing and sources Checked October 8, 2026	Official website Full listing and sources Checked October 2, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.