Xml Validation Websites
lxml - Processing XML and HTML with Python
lxml - the most feature-rich and easy-to-use library for processing XML and HTML in the Python language
188,767 
$ 36,600.00
XML Validation: XML Validation
A web-based XML validator. Can be used for free. Validates XML files, prompts the user for referenced files (e. g., XSD), shows good error messages.
265,247 $ 19,440.00
SAP® StreamWork™
A web-based XML validator. Can be used for free. Validates XML files, prompts the user for referenced files (e. g., XSD), shows good error messages.
249,851 $ 20,520.00
HTTPUtility.net - collection of online utilities for developers
Collection of utilities frequently needed in web development, such as testing URL encode/decode, HTML encode/decode, generating runtime classes from a XSD or a JSON string and many more
1,232,724 $ 480.00