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Chrome extension source viewer (CRX Viewer)

View the source code of any Chrome extension in the Chrome Web store without installing it.

Also available for Opera and Opera's add-on gallery.

And also available for Firefox and (WebExtensions and other Firefox addon types).

Online demo (select a .crx / .nex / .zip / .xpi from your disk or a URL to try out the viewer):


This Chrome extension adds a button to right of the omnibox when a CRX file has been detected. This button appears in the following extension stored:

  • Chrome Web Store
  • Opera add-ons gallery
  • Firefox add-ons gallery
  • Thunderbird add-ons gallery
  • Microsoft Edge Addons store

Upon clicking the button, two actions become available:

  • Download extension as zip file
  • View source

The default action (showing the above options) can be changed via the "Primary action on click" menu that appears when you right-click on the extension button.

The "View source" option opens a new tab with a simple viewer, with the following features:

  • Download-as-zip and download-as-crx at the upper-right corner.
  • List of file names, and the option to filter files with a regular expression.
  • Find files containing a string, or with content matching a regular expression.
  • Quickly jump between search results, or from/to a specific line.
  • Automatic beautification (formatting) of code
  • Syntax highlighting
  • Image preview
  • Show hashes (md5, sha1, sha256, sha384, sha512) of the file content.
  • View content of embedded zip files.
  • Download Chrome Web Store extensions for a different platform (e.g. Chrome OS or NaCl).
  • View the contents of any URL or zip file.
  • Permalink to file and search result within a zip or extension file.

As mentioned before, this extension activates on the Chrome Web Store by default. It's also possible to view the source code of Chrome, Opera 15+ and Firefox extensions that are hosted elsewhere. Further, there is an option to show a contextmenu entry on links whose target is a Chromium extension. Both features can be toggled at the options page.


(c) 2013 - 2022 Rob Wu (

This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at


Add-on / web app to view the source code of Chrome / Firefox / Opera 15 extensions and zip files.







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