JSONFormatter.org - Online JSON Formatter and JSON Validator will format JSON data, and helps to validate, convert JSON to XML, JSON to CSV. Save and Share JSON
ProtoPie - ProtoPie is the easiest tool used to turn your UI/UX design ideas into highly interactive prototypes for mobile, desktop, web, all the way to IoT.
FreeFormatter - Freeformatter is a platform that contains free online tools for developers, including formatters (json, html, xml, sql, etc.), minifiers (css, javascript), compactors, validators, and much more.
Prototypr Makerspace - Design and prototype your ideas with the community
Web Tool Kit Online - Web Tool Kit Online is a website that provides an online tool for developers helping them to develop an application in C++ without any hurdle.
Inspr - Mock-up app designs right from your iPhone