Whilst the W3C do provide an excellent service for manually checking your web pages, there are times when an alternative is required.

There is for example a web service at http://validator.w3.org/docs/api.html  This can be for programmatically checking your pages (provided you make no more than 1 call per second).

The W3C do provide all the source code needed to run your own validation service. Get the full details at:

·         Installation and development information for the W3C Markup Validator   http://validator.w3.org/docs/devel.html

·         Source Availability http://validator.w3.org/source/