Website Validation by W3C

Quickly and easily perform website validation by the same organization that builds Web standards.

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Right tool

The World Wide Web Consortium (W3C) Validator Suite service provides a new integrated view for evaluating website quality. Validator Suite integrates Web standards conformance tools to make it easy and quick to keep your website compliant with Web standards. Valid, standards-compliant code is the cornerstone of the Open Web Platform success. Valid code just works.

Mark of success

Developers, designers and site managers have used W3C's free Validator tools millions of times a day, for more than 15 years. W3C builds on that experience now with enhanced validity and efficiency. Soon we will add checking capabilities for accessibility, compatibility, and optimization.


W3C Validator Suite examines the public pages of an entire website and evaluates conformance with W3C open standards. It is available as an online service (SaaS) that provides:


I'd like to say how important your service has become to my business! [...] it's unsettling to see how many do not even know there are standards! I'm proud to be able to have potential clients see that my designed websites are to your standards.

Web designer

I have used your free validator since day one. When I saw this new service, it became clear how I could do an entire website with one click!

Web designer

The W3C Validation is vital to my success. Case in point: A friend told me, "I like viewing your web sites. They work."

Web developer

A sample W3C Validator Suite report
Screenshot of a W3C Validator Suite report


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