JSONView is a Safari web extension that helps you view JSON documents in the browser. This is a Port of JSONView(http://jsonview) by Benjamin Hollis
Normally when encountering a JSON document (content type application/json), Safari simply prompts you to download the view. With the JSONView extension, JSON documents are shown in the browser similar to how XML documents are shown. The document is formatted, highlighted, and arrays and objects can be collapsed. Even if the JSON document contains errors, JSONView will still show the raw text.
Once you've got JSONView installed, check out this example JSON file to see the extension in action!