Some excellent JSON tools

http://jsonlint.com/ - I use this to format and validate JSON I'm working with. Wonderfully simple and responsive interface.

http://json.bloople.net/ - A great tool to make exploring possibly large JSON data easier. Also useful for showing the content of JSON to a semi-technical audience.

https://github.com/FasterXML/jackson - Jackson is a fantastically flexible tool for working with JSON in Java. Jackson + Lombok make my API classes super trim and easy to enhance. I'll write a quick tutorial on this sometime.

Programming Tool Reviews

I'm a tools guy. With the right tools, hard jobs become easy. Finding good tools can be difficult and as time passes, the best tools for a given job change. I'll be writing posts here to document the tools I find and my experiences with them.