2FA Authenticator Assistant by wzf

2FA Authenticator Assistant (2FA 验证助手) is the browser companion for the open-source wuzf/2fa project. Connect your own instance to view, copy and fill time-based one-time passwords (TOTP). It supports 15 languages in one extension: Simplified Chinese, Traditional Chinese, English, Japanese, Korean, German, French, Spanish, Portuguese (Brazil), Italian, Russian, Turkish, Indonesian, Vietnamese and Thai. The interface follows your browser language or a manual selection in Display language. Unsupported browser languages use English.

A self-hosted instance is required. Deploy the project, add your accounts and sign in to that instance in a normal tab of the same Firefox profile (the default container on desktop) before connecting the extension. The extension does not provide hosted accounts and does not connect directly to arbitrary authenticator products.

Features
• View current and upcoming codes; search by service, username or email.
• Pin frequently used accounts and remember account bindings for individual websites.
• Fill a code with the account's Fill button or Ctrl+Shift+U (Command+Shift+U on macOS). On Android, open the extension from the browser's extension menu; there is no extension shortcut.
• Explicitly enable automatic filling for a website, on HTTPS or HTTP (including private network addresses), while filling a code or with “Autofill on this website”. After you approve access to that site, the extension detects code fields on its pages. It fills the remembered account or a unique reliable match, or offers a choice of matching accounts.
• Work with common single-field and segmented code inputs, accessible same-origin frames and open Shadow DOM. Copy and paste remains available when a page is incompatible.
• Switch between self-hosted instances while keeping each instance's website bindings separate.

Connection options
The default mode uses your existing website login session. The extension retrieves account secrets from your configured instance and calculates codes temporarily in its background process without persistently storing the seeds. The instance's tab may be closed, but code generation requires a working connection and a valid login session.

You can explicitly enable "Allow offline use" (允许离线使用). After synchronization, the extension stores the current instance's account secrets and time calibration in this browser and can calculate codes after the instance tab is closed, the browser restarts or the network becomes unavailable. This local cache contains raw secrets and has no additional password encryption; enable it only on a trusted device. Turning offline use off, switching instances or revoking instance access deletes this extension cache. Uninstalling deletes the extension's local data. While offline, the extension cannot immediately learn about server-side account deletion or session revocation.

Permissions and data
Site access is requested only when you configure an instance or explicitly enable automatic filling for a target website. Automatic filling is additionally restricted to the authorized full origin (scheme, host and port), or to a single page if you limit it in the settings. Copying uses the clipboardWrite permission only to write the code you copy; the extension never reads the clipboard. Settings, account bindings and favorites stay in the current browser and are not synchronized through your Firefox account.

The extension handles account names, usernames, TOTP secrets and codes, and reads the page structure needed to fill a code. On an identifiable Google TOTP page, it can use the displayed signed-in email to match the account. This processing serves code display, matching and filling only. Filling shares the selected code with the target page; a multiple-account panel displays names and usernames for that site's candidates. The complete account vault and seeds are not provided to target websites.

The “authentication information” and “personally identifying information” shown in the Firefox install prompt disclose this necessary exchange of authentication data and candidate account details. There are no ads, telemetry or developer relay service. Online requests go to your configured instance for accounts, server time and service icons; that instance and its hosting provider receive normal network requests. The extension does not click Submit, although a website may submit its own form after the code is filled.

For Firefox 153 or later on desktop and Android, in normal tabs (the default container on desktop). Private browsing, desktop container tabs and counter-based HOTP codes are not supported.

Project: https://github.com/wuzf/2fa
Deployment guide: https://github.com/wuzf/2fa/blob/main/docs/DEPLOYMENT.md
Support: https://github.com/wuzf/2fa/issues