W3C Markup Validator

W3C Markup Validator is listed in our database as a program that opens or converts the file formats shown on this page. It runs on Web. The formats it works with include .XHTML.

You can get the official version from the developer's website (validator.w3.org); we do not host the installer and only point you to the original source. A detailed, hand-checked description of W3C Markup Validator is on the way; for now the information here comes straight from our database.

Click any badge for full per-format details - what it is, how to open it and how to convert it.