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