Tools

Apiary – Service for API mockup and testing
http://apiary.io/

JSON Editor
https://www.jsoneditoronline.org/

JSON Validator
http://jsonlint.com/

CSS3 Generator
http://css3generator.com/

CSS3 Playground
http://css3.mikeplate.com/

CSS3 Button generator
http://css3button.net/

Ultimate CSS gradient generator
http://www.colorzilla.com/gradient-editor/

CSS 3.0 Maker
http://css3maker.com/

FavIcon Generator
http://tools.dynamicdrive.com/favicon/