jigsaw.w3.org
About
The W3C CSS validator is written using the java language, and yes, its source is available, using Git: you can browse the code online or follow the instructions there to download the whole source tree. For a quick overview of the classes used in the CSS Validator code, check out the README file. Can I install and run the CSS Validator myself?
English
English - The W3C CSS Validation Service
Documentation
Informations about the CSS Validator, and answers to some general questions CSS Validator FAQ Answers to technical questions frequently asked. Translator's Corner Translation of the CSS Validator Table of the state of all current translations, translations needing help, and instructions on making the validator available in an additional language.
Acknowledgments
Acknowledgments The CSS Validation service is being maintained at W3C as an open source project, by W3C staff and volunteers, under the auspices of the Quality Assurance tools development effort "qa-dev".
User Manual
CSS Validator Web Service API: SOAP 1.2 validation interface documentation For more technical help, in particular about the SOAP 1.2 output and all the possible ways to call the validator, see the CSS Validator Web Service API.
Nederlands
Nederlands - The W3C CSS Validation Service