If you install a Google Chrome extension (like a dark mode enabler or a grammar checker), Chrome seamlessly downloads the code from the Web Store and injects it into your browser. If you are a developer, you might be curious about how a specific extension works. Or, if you suspect an extension is secretly tracking you, you might want to inspect its raw code.
Extensions are written in standard web languages (HTML, CSS, and JavaScript). Chrome stores the unencrypted, raw source code for every extension directly on your hard drive. You can safely extract this code and view it in any text editor without needing special reverse-engineering tools.
How to Safely Extract Chrome Extension Source Code
You must find the extension’s unique ID and locate its folder in the Chrome User Data directory.
- Open Google Chrome, click the three vertical dots in the top-right corner, select Extensions, and click Manage Extensions.
- In the top-right corner of the Extensions page, toggle Developer mode to On.
- Find the extension you want to inspect in the list. Under its description, you will now see a string labeled ID: followed by 32 random letters (e.g.,
cjpalhdlnbpafiamejdnhcphjbkeiagm). Keep this page open. - Open File Explorer (Windows Key + E) and navigate to the following path:
%LocalAppData%\Google\Chrome\User Data\Default\Extensions - You will see a list of folders named with those 32-letter IDs. Match the ID from Chrome to the correct folder and double-click to open it.
- Open the version number folder inside (e.g.,
1.5.0_0).
You are now looking at the complete, raw source code of the extension. You can open the manifest.json file in Notepad to see exactly what permissions the extension requires. You can open the `.js` (JavaScript) files to read the actual logic and algorithms the developer wrote to make the extension function. Because you are only reading the files, the extension will continue to work normally in Chrome.