mozilla/html5-lint

html5-lint is a front-end tool for validating HTML5 code using Mozilla's HTML5 Validator instance, designed to integrate seamlessly into build systems for automated HTML error checking. It provides both Node.js and Python interfaces, making it ideal for developers working on Mozilla projects or anyone seeking to validate HTML5 code without overloading the main validator service. The tool is particularly useful for build systems that require automated HTML validation, offering options to filter errors, warnings, and output formats.