The easiest way to validate and format JSON. This is the validating and formating JSON tool from pro.jsonlint.com.
JSON Viewer, JSON Editor and JSON Validator.
This is the original validating and formating JSON tool from pro.jsonlint.com
Props to Douglas Crockford of JSON and JS Lint, and Zach Carter, who provided the JS implementation of JSONlint.
I've has been slightly suited it and added some shortcuts, so that it works as a real Chrome app.
Internet connection is just needed if you paste an URL to parse it. In any other cases it works offline and don't need any connection!