JSON viewer

Firefox includes a JSON viewer. If you open a JSON file in the browser, or view a remote URL with the Content-Type set to application/json, it is parsed and given syntax highlighting. Arrays and objects are shown collapsed, and you can expand them using the “+” icons.

The JSON viewer provides a search box that you can use to filter the JSON.

You can also view the raw JSON and pretty-print it.

Finally, if the document was the result of a network request, the viewer displays the request and response headers.