XML Copy Editor - XML Copy Editor is a fast, free, validating XML editor.
Jayson - Powerful JSON viewer for iPhone and iPad
Altova XMLSpy - The XMLSpy XML Editor is a powerful tool for editing XML and related technologies. It is the only XML Editor with patented SmartFix validation, enterprise-grade editors, converters, debuggers, and code generators.
Code-Free Startup - Learn how to build real apps without coding
Oxygen XML Editor - Oxygen XML Editor provides a comprehensive suite of XML authoring and development tools.
KickAppBuilder - Create Your Mobile App for FREE. No coding required.