validator/validator

Health v2 · maintenance only

Adoption not part of the score

1980 stars · 332 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

The Nu Html Checker (vnu) is the W3C/WHATWG-endorsed tool for validating HTML, CSS, and SVG documents. It runs as a command-line batch checker, a standalone web service, or a servlet-deployable WAR, with pre-compiled binaries, a portable JAR, Docker image, and npm/brew packages.

Use cases

• validate html files for errors
• check css and svg markup mistakes
• batch-validate a directory of web pages from the command line
• self-host an html validation service like validator.w3.org/nu
• integrate html validation into ci or build tools like grunt or gulp
• lint html in automated scripts

When to choose

• you need standards-compliant HTML/CSS/SVG validation matching validator.w3.org/nu
• you want to batch-check many files or URLs from the command line
• you want to self-host a validation service via Docker, WAR, or standalone server
• you need cross-platform binaries that don't require Java installed

When to avoid

• you need linting beyond markup validation, such as JavaScript linting or style enforcement
• you want a browser-based GUI validator without running anything locally
• you need a lightweight pure-JS linter inside a Node build pipeline without Java or binaries

Facets

cli-tool · maturity stable

linter cli http-server developer-tools web-development developer-tools documentation windows cli self-hosted jvm cross-platform html-validation html-checker css-validation svg-validation w3c whatwg web-standards vnu java servlet npm-package brew-package command-line linux macos docker

Member repositories

For agents

markdown · JSON · MCP: product_card(name="validator/validator")