How to use CRX Viewer to inspect a Firefox addon?

Install the CRX Viewer extension for Firefox from addons.mozilla.org, then navigate to any Firefox addon page on the gallery; a button will appear to view the source code directly in a new tab with syntax highlighting.

Does CRX Viewer work with Safari extensions?

No, CRX Viewer currently supports Chrome, Firefox, Opera, Thunderbird, and Edge extensions; Safari extensions are not supported due to different store formats and lack of integration in the README's listed stores.

Can I download an extension as a CRX file using CRX Viewer?

Yes, in the viewer interface, you can download extensions as CRX or ZIP files, and even fetch versions for different platforms like Chrome OS, as mentioned in the features section.

How to search for specific code in an extension with CRX Viewer?

Use the advanced search feature in the viewer to find files containing strings or matching regular expressions, with quick jump navigation between results and specific lines for efficient code analysis.

Is CRX Viewer safe to use for security auditing?

Yes, it allows viewing source code without installing extensions, reducing risk; features like file hashing help verify integrity, but always audit code from trusted sources due to potential vulnerabilities.

CRX Viewer vs Chrome DevTools for extension inspection

CRX Viewer is better for quick, no-install source viewing from stores, while Chrome DevTools require extension installation for runtime debugging, making them complementary tools for different stages of analysis.

What are alternatives to CRX Viewer for viewing extension source?

Alternatives include manually downloading CRX files and extracting them with tools like unzip, or using browser developer tools on installed extensions, but CRX Viewer offers integrated store access and advanced features like regex search.

Open-Awesome

Chrome extension source viewer

MPL-2.0JavaScript

Browser extension and web app to view source code of Chrome, Firefox, Opera, and Edge extensions without installing them.

Visit Website GitHub

1.7k stars262 forks0 contributors

What is Chrome extension source viewer?

CRX Viewer is a browser extension and web application that enables developers to view the source code of Chrome, Firefox, Opera, and Edge extensions directly from their respective web stores without installation. It solves the problem of needing to install extensions just to inspect their code, making it easier to analyze, learn from, or audit extension functionality and security.

Target Audience

Browser extension developers, security researchers, and web developers who want to inspect, learn from, or audit the code of extensions available in public stores like Chrome Web Store or Firefox Add-ons.

Value Proposition

Developers choose CRX Viewer because it provides a seamless, integrated way to view extension source code directly from store pages, with advanced features like regex search, syntax highlighting, and file hashing, all without requiring installation of the target extensions.

Overview

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

Use Cases

Best For

Inspecting Chrome extension source code before installation
Learning how popular browser extensions are built
Security auditing of third-party extensions
Analyzing extension file structures and embedded resources
Downloading extensions as ZIP files for offline analysis
Viewing source code of Firefox, Opera, or Edge add-ons

Not Ideal For

Developers needing real-time debugging of running extensions
Projects analyzing extensions hosted outside supported stores
Users who want to directly edit and repackage extension code
Teams requiring automated, scriptable access to extension sources

Pros & Cons

Pros

Universal Store Integration

Adds buttons directly to Chrome, Firefox, Opera, Thunderbird, and Edge store pages, enabling one-click source viewing without manual download, as specified in the README's store list.

Advanced Code Inspection

Features like regex search, syntax highlighting, and automatic beautification make code analysis efficient, with quick navigation between results and specific lines, per the README.

Flexible File Handling

Allows downloading extensions as ZIP or CRX files, viewing embedded zips, and showing file hashes (MD5, SHA256, etc.), useful for offline analysis and security audits.

Cross-Platform Compatibility

Works as a browser extension for multiple browsers and has an online demo for viewing any URL or ZIP file, ensuring broad accessibility.

Cons

View-Only Functionality

Solely a viewer with no editing capabilities; users cannot modify or repackage extensions within the tool, requiring external software for development tasks.

Store Dependency

Relies on the structure of official store pages for detection, so changes in store layouts or APIs could break functionality without updates.

No Runtime Analysis

Only displays static source code, lacking tools for inspecting extension behavior during execution, which limits use for dynamic debugging or performance profiling.

Frequently Asked Questions

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