The Markup Validator is a free service by W3C that helps check the validity of Web documents. It checks the syntax of Web documents, written in formats such as (X)HTML. The API uses SOAP protocol and responses are formatted in XML.
When designing web pages, we use any tools we can get our hands on to make the experience easier and faster. Today we're going to take a look at 10 web design APIs that, in different ways, can be very useful.