In other words, JSON is a good choice for data to be shuttled back and forth between web services via AJAX thanks to its clean and compact nature.
However, debugging a big chunk of JSON is not always the easiest task, particularly when it appears to be fault. Enter Chris Dary and his fantastic JSON validator and reformatter, JSONLint!
Simply copy or paste your JSON text into the big text box and hit the validate button, and JSONLint will make it look nice and spit out any validation errors it encounters while attempting to parse it. You can also feed it an URL, which it will then take and grab any JSON it detects from its source.
Additionally, if you are looking to squeeze your JSON to as small a form as possible, you can use JSONLint as a JSON compressor if you add ?reformat=compress to the URL.
Excellent free online tool, and well worth checking out if you do a lot of work with JSON.
Related Link: http://jsonlint.com/