Firefox’s JSON viewer is not working [Full Fix]

by Matthew Adams
Matthew Adams
Matthew Adams
Windows & Software Expert
Matthew is a freelancer who has produced a variety of articles on various topics related to technology. His main focus is the Windows OS and all the things... read more
Affiliate Disclosure
  • If you have problems with Firefox's JSON viewer, there is a problem with the browser.
  • You can easily get rid of the Firefox JSON viewer not working error by switching to another browser.
  • Using our method to enable the setting in Mozilla is another easy way to fix the issue.
  • Still having issues? Try one of our alternative add-ons and web tools below.
Fix Firefox's JSON viewer or use add-ons and web tools

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JSON, otherwise JavaScript Object Notation, data is a protocol for browser/server communication and one of the primary alternatives to XML.

However, JSON data is not readable by developers without a JSON viewer that structures and displays the data in a clear way. As such, Mozilla has incorporated a JSON viewer in Firefox.

How do I view JSON in Firefox? The quickest way to view and edit JSON data in Firefox is through its integrated JSON viewer. The data viewer is enabled by default only in the Developer Edition and Nighly. If that doesn’t suit you, use some useful add-ons and web tools for Firefox.

For more information about that, check the guide below.

Note: The following steps are equally helpful if you were looking for the following issues:

  • firefox json viewer not working
  • firefox json extension
  • mozilla json viewer
  • firefox json expand all

How do I fix JSON viewer on Firefox?

1. Consider using a different browser

Before trying any of the troubleshooting solutions below, we would first like to suggest that you consider using a different browse entirely.

For example, Opera is an excellent choice for use if you are interested in JSON Viewer, since it also comes with its own JSON extension called JSON Lite.

The browser has proven itself to be far more stable and reliable than the Firefox variant. More so, Opera is a great web browser as a whole, featuring an incredibly modern UI with high levels of customization.

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It has a built-in VPN and ad-blocker, and it is base on the Chromium engine, making it compatible with extensions from both Chrome and Edge as well.



If you’re interested in running a JavaScript Object Notation session on your browser, then why not try out this amazing tool for a change?

2. Enable JSON Viewer in Firefox

  1. First, enter the following in Firefox’s address bar: about:config
  2. Then, press the Return key to open the page shown in the snapshot directly below.
  3. Next, input the following into the search bar at the top of the about:config page: devtools.jsonview.enabled
  4. Now you can double-click devtools.jsonview.enabled to switch its value to True.
  5. That effectively enables the JSON viewer in Firefox browser.

If Firefox’s JSON viewer isn’t working for you, that’s probably because it’s not enabled. At the moment, the data viewer is only enabled by default in Developer Edition and Nightly.

3. Try alternative JSON Viewer add-ons and web tools

  1. Add JSONView to Firefox by pressing the +Add to Firefox button on this page.
  2. After you’ve added the add-on, open this page to see an example of some formatted JSON data.
  3. Before, you should see your data as such.
  4. After installing the addon, it should look like this.

JSON-Data View

  1. Go to this page and add the extension to your browser.
  2. Open the page again to check its JSON data formatting style.
  3. The data should now include + and – buttons to expand and collapse tree nodes, syntax highlighting, and hyperlinks.

The JSON-DataView also includes customization options that you can select by following the steps below:

  1. Click on the Open menu button at the top right of the browser.
  2. Then click on Add-ons.
  3. Press the Options button beside JSON-DataView to open the windows shown below.

JSON web viewer

  1. Copy and paste your data into this JSON viewer’s text tab.
  2. Try copying and pasting the JSON data below with the Ctrl + C and Ctrl + V hotkeys: {"hey": "guy","anumber": 243,"anobject": {"whoa": "nuts","anarray": [1,2,"three"], "more":"stuff"},"awesome": true,"bogus": false,"meaning": null, "japanese":"明日がある。", "link": "", "notLink": " is great"}
  3. After you’ve copied the text, press the Format button.
  4. The data will then be displayed as shown in the picture below.

JSON Editor Online

The JSON Editor Online is another web tool you can display data in from HDD or URL. You just need to open the web tool and copy-paste the sample data above into the code editor.

Press the right arrow button to copy the code into the tree editor, and then click the left arrow button to display the JSON data as shown below. There, you can edit the data and save any changes made.

The page also includes a handy search tool for fields and values.

If you need a JSON viewer, the built-in Firefox viewer doesn’t do everything you need. As such, JSON add-ons and web tools are great alternatives for developers who need to open and edit JSON data.

Hope that this was helpful and you’re now aware of the different JSON add-ons and web tools you can use. If you have any more questions, feel free to reach for the comments section below.

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