I am looking for a JSON viewer for OS X that can:

  • open decently large files (e.g. > 10 MB), unlike the JSON Editor Eclipse Plugin (take over 1 minute to generate the treeview for a 500 KB JSON file) and Json Tools Eclipse Plugin (no outline generated if file is more than a few MBs but otherwise great and fast)
  • has a decently responsive UI, unlike JSON Viewer for Windows
  • can collapse/expand a given level (treeview / outline)
  • works off-line


  • tabs
  • gratis
  • can edit JSON data
  • displays the filename somewhere, unlike JSON Viewer for Windows
  • provide some statistics on the JSON content

4 Answers 4

  • Jsoneditor is a browser-based editor that you can deploy locally or use the ad-sponsored online version provided by the author. It's handy for small JSON files, and I find it the easiest and most feature-full. It will highlight broken json, but it's not a 100% compatible validator like https://jsonlint.com/ because, for example, it treats raw tabs as valid within strings although this is not allowed by the JSON spec.

  • JSONMate seems to be a usable open-source project with an online editor which probably won't be able to handle large files, but you can fork it on github, adapt to your needs and run it locally.

  • Intellij Idea and derivatives have decent JSON support, but large files take time to load.

  • SublimeText is also usable for JSON if you install the plugins for beautifying and extra features.

For windows XMLMarker does a good job as an XML and JSON visualizer, but the last version which added JSON support is a limited trial.

Disclaimer: I am not affiliated with any of these tools, authors or projects.


Checkout Jason, although it appears to be no longer maintained since Osx 10.7, I just opened a JSON in it with Osx 10.11 and it works ok.

Please Note: since it is no longer maintained it is likely going to be unreliable.

Alternatively, I have opted for an online browser-based JSON editor:

It is surprisingly fast, allowing you to browse the tree, search values, edit values, insert values, reorder values, even duplicate values. You can even drag and drop stuff around to really get creative :) Unfortunately, you can't see the filename of the json you are editing, but you can open up new browser tabs for multiple json file editing at once.

  • Online editors are good but they have performance problems with bigger files, sometimes they are not even able to open them.
    – Sulthan
    Sep 28, 2018 at 9:03

Just stumbled upon https://jsonviewer.app.

Native, responsive, has tree view, works offline.

No tabs.

Works with large files with one big caveat – you can't open a file directly from the filesystem. Rather you have to copy-paste the content into the app, so you are limited by the maximum size you are able to fit in the clipboard. I was able to paste a 10MB+ file, but not a 100MB+ file.


I use Brackets editor to browse json files. Works great!

  • I got an error: "Files larger than 16MB cannot be opened in Brackets"
    – JP Duffy
    Oct 4, 2018 at 14:32

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