lxml - the most feature-rich and easy-to-use library for processing XML and HTML in the Python language
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.
XMLdation® is the leading provider of end-to-end testing and simulation services for payment-related XML messages. The company’s unique cloud-based SaaS solution assists banks, vendors and corporates in the migration to XML-based financial transactions, their maintenance and holistic XML management.
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