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Application security tools

Application security / FREE TOOL

Free Browser Extension Security Review

Review extension permissions, injected scripts and messaging boundaries. Import a Chrome Web Store link or paste a Chrome or Firefox manifest.

Local review / optional AI

01 Your input

Paste the store link or extension ID. We fetch its published manifest, then review it here without installing or running the extension.

Store lookup sends only the extension ID to BreachLine and Google. Pasted files stay in this browser.

Local processing only. Maximum file size: 2 MB.

02 Your results

A closer look starts here.

Add your input and run the check. We will show the observations and explain what needs review.

 

A QUICK WALKTHROUGH

How to use it

  1. 01Paste a Chrome Web Store link or extension ID to fetch and review its manifest, or select a local manifest.json file. If you only know its name, use the store search to select the exact listing.
  2. 02Review required and optional capabilities, host scope and trust boundaries. Store imports include the retrieved version, timestamp and manifest fingerprint.
  3. 03Compare these declarations with the extension purpose and inspect its JavaScript using the JavaScript review tool.

What this check can tell you

Reviews manifest declarations without installing or running the extension. Optional Chrome Web Store import fetches the published manifest through BreachLine; pasted files are processed locally. Package identity and archive integrity checks do not verify the signing chain, publisher trust, bundled code or runtime behavior, and cannot determine whether an extension is malicious. Maximum imported manifest size: 200 KB.

The initial review processes files in this tab. If you choose the optional AI summary, the displayed findings are sent to Cloudflare AI; your raw file, result tables and decoded token claims are excluded.

Chrome extension permission guidance

Copy this HTML to link to the Browser extension review.

<a href="https://breachline.io/tools/extension-review">Browser extension review</a>
 
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