Osmium is a privacy-first, fully offline authenticator for two-factor codes (TOTP/HOTP): codes are generated on-device and work without any network connection.
• Codes are computed entirely on-device — no account, no sign-up, and no telemetry.
• No connections at start-up. Osmium goes online only when you ask it to: the automatic update check is off by default, and the Terms of Use / Privacy Policy are downloaded from osmium.im only when you open them.
• Secrets are encrypted with a non-exportable key in the Android Keystore before they are written to disk.
• TOTP and HOTP: 6/7/8 digits, SHA-1/SHA-256/SHA-512; Steam Guard codes supported.
• Organize accounts with tags and search.
• Import from other apps: Google Authenticator (QR migration), Aegis, 2FAS and other common backup formats.
• Encrypted export & restore to a local file or your own WebDAV server; encrypted quick transfer between two devices on the same Wi-Fi.
• Modern Material 3 design with light/dark themes and Material You colours.
• Fully open source (GPL-3.0-or-later); release builds are reproducible — anyone can verify that the published APK matches the source code.
No ads, no trackers, no analytics.
Website: https://osmium.im
Source code: https://github.com/lihongxi-g/osmium-authenticator
