KeePassXC-Browser is a free, GPL-3.0 browser extension for Firefox, Chrome/Chromium, and Microsoft Edge that connects those browsers to a locally running KeePassXC password database over native messaging.

What it is

KeePassXC-Browser is the official browser extension for KeePassXC, the desktop password manager. It lives in the WebExtensions ecosystem and is written in JavaScript, with the extension itself published through the Firefox, Chrome/Chromium, and Microsoft Edge add-on stores. It has been supported by KeePassXC since version 2.3.0, released at the end of 2017, and it communicates with the desktop application using the native messaging API rather than by reading or writing the database file directly.

The concrete thing it replaces is the browser's own built-in password manager. The extension requests the privacy permission specifically so it can register itself as the default password manager, and it takes over credential entry on http:// and https:// pages, including HTTP Basic Auth dialogs handled through the webRequest, webRequestAuthProvider, and webRequestBlocking permissions. Credentials never leave the machine they are stored on, because all secret handling stays inside KeePassXC and the extension only relays requests.

Key capabilities

• Communicates with KeePassXC through keepassxc-proxy, which listens on STDIN/STDOUT and forwards messages over Unix domain sockets or named pipes.
• Ships keepassxc-proxy inside the KeePassXC application package, so no separate proxy install is required.
• Supports keepassxc-proxy-rust as an alternative proxy for users who prefer a non-Qt solution.
• Handles HTTP Basic Auth in Chromium-based browsers through the webRequestAuthProvider permission.
• Provides a password generator whose output can be copied to the clipboard via the clipboardWrite permission.
• Stores extension settings locally in the browser through the storage permission, and never syncs them.
• Documents the browser-to-KeePassXC messaging format in keepassxc-protocol.md.

Who uses it and how

• Desktop users running KeePassXC 2.3.0 or later who want autofill in Firefox, Chrome/Chromium, or Microsoft Edge without exporting their database to a cloud service.
• Translators, who work through Transifex language teams rather than through pull requests against the source tree.
• Contributors submitting pull requests, guided by .github/CONTRIBUTING.md, with the hacktoberfest topic marking the repository as open to outside contribution.
• Developers and testers who load the extension manually using the instructions in the repository wiki.

Getting started

Install the extension from Firefox Add-ons, the Chrome Web Store, or Microsoft Edge Add-ons, then follow the browser integration section of the KeePassXC Getting Started document to connect the desktop application to the extension.

How it compares

The facts name no rival password-manager extensions, so this project stands alone in this registry among browser-extension password managers. The only related projects named are KeePassXC itself, which is the required desktop counterpart, and keepassxc-proxy-rust, which is an alternative implementation of the same proxy rather than a competing product.

When to use it — and when not to

A self-hoster must run the KeePassXC desktop application, since the extension is useless without it and the bundled keepassxc-proxy; there is no hosted or server-side option, and settings are local to each browser profile. Anyone who does not already use KeePassXC, or who needs credentials synced across devices by the password manager itself, should look elsewhere. The honest weaknesses are the 197 open issues and the thin in-repository documentation, which defers configuration and problem solving to the KeePassXC website and the project wiki.