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A Firefox extension that helps you view JSON documents in the browser.

branch: master


JSONView is a Firefox extension that helps you view JSON documents in the browser.

Normally when encountering a JSON document (content type "application/json"), Firefox 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!

CouchDB users and others who need to have "application/json" sent in the HTTP Accept header to serve JSON properly should set that option in JSONView's options panel. Be aware that telling sites that you accept JSON can mess up some sites that don't expect it.

If you'd like to contribute to JSONView but don't want to code, consider contributing a translation. Just go to BabelZilla and register as a translator for the JSONView extension. There's not much there to translate!

Reporting Issues

Use the GitHub Issue tracker for JSONView to file issues. Pull requests are especially welcome.

Developing JSONView

  • Install Add-on SDK
  • Make sure the SDK Virtual Environment is activated by running cfx from shell prompt.
  • Run python run to test in Firefox.
  • Run python xpi to create an xpi.
  • Run python fix to fix localized description in the generated xpi. See Bug 661083.

Unofficial Ports

Common Issues

  • JSONView isn't displaying my file as JSON: You are probably not serving the JSON with the "application/json" MIME type.
  • JSONView is mangling large numbers: Here's the explanation.

JSONView is open source software under the MIT licence.

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