Firefox Browser Add-ons
  • Extensions
  • Themes
    • for Firefox
    • Dictionaries & Language Packs
    • Other Browser Sites
    • Add-ons for Android
Log in
Preview of FactorCat - MFA Authenticator

FactorCat - MFA Authenticator by FactorCat

FactorCat detects MFA fields, sends a push to approve, and auto-fills the code. Your TOTP secrets never touch the browser - the extension is architecturally prevented from holding them. Free to use.

0 (0 reviews)0 (0 reviews)
Download Firefox and get the extension
Download file

Extension Metadata

Screenshots
Automatic entry of 2FA tokensAutomatic entry of 2FA tokens
About this extension
FactorCat replaces the MFA copy-paste routine with a single approval.

The extension detects MFA input fields on login pages, matches the site against your token inventory by domain, and requests approval. Approve from your phone or the web dashboard, and the six-digit code fills in automatically.

ZERO-TRUST ARCHITECTURE
The browser extension is architecturally prevented from ever holding a TOTP secret. It receives only a computed code, only after you approve the request. Secrets are stored server-side in encrypted cloud vaults or locally on your mobile device — never in the browser.

KEY FEATURES
- Auto-detection of MFA fields on login pages
- Push-to-approve via mobile app or one-click approve from the web dashboard
- Automatic code fill — no typing, no clipboard
- Domain-based token matching with display-name picker for multi-token domains
- QR capture on MFA setup pages — add tokens without your phone camera
- Fallback to clipboard and on-screen code display when auto-fill isn't possible

HOW IT WORKS
1. Visit a login page that asks for an MFA code
2. FactorCat detects the input field and matches your token
3. Approve the request — from a push notification on your phone or directly in the web dashboard
4. The code fills in automatically — you're logged in

SECURITY BY DESIGN
- TOTP secrets never enter the browser — stored in cloud vaults or on your mobile device
- The extension only receives computed codes, never raw secrets
- All communication is encrypted end-to-end
- Biometric confirmation available for mobile approvals
- MFA and passwords stay separate — no single point of failure

WORKS WITH OR WITHOUT THE MOBILE APP
Cloud vaults work with just the web dashboard — no mobile app required. Add the mobile app later for push notifications, biometric approval, and locked vaults with on-device encryption.

Free to use. Learn more at factorcat.com
Rated 0 by 0 reviewers
Log in to rate this extension
There are no ratings yet

Star rating saved

5
0
4
0
3
0
2
0
1
0
No reviews yet
Permissions and data

Required permissions:

  • Access your data for all websites

Data collection:

  • The developer says this extension doesn't require data collection.
Learn more
More information
Add-on Links
  • Homepage
  • Support site
Version
1.0.0
Size
155.09 KB
Last updated
4 days ago (Apr 5, 2026)
Related Categories
  • Privacy & Security
License
All Rights Reserved
Privacy Policy
Read the privacy policy for this add-on
Version History
  • See all versions
Tags
  • password manager
  • privacy
  • security
Add to collection
Report this add-on
Go to Mozilla's homepage

Add-ons

  • About
  • Firefox Add-ons Blog
  • Extension Workshop
  • Developer Hub
  • Developer Policies
  • Community Blog
  • Forum
  • Report a bug
  • Review Guide

Browsers

  • Desktop
  • Mobile
  • Enterprise

Products

  • Browsers
  • VPN
  • Relay
  • Monitor
  • Pocket
  • Bluesky (@firefox.com)
  • Instagram (Firefox)
  • YouTube (firefoxchannel)
  • Privacy
  • Cookies
  • Legal

Except where otherwise noted, content on this site is licensed under the Creative Commons Attribution Share-Alike License v3.0 or any later version.