QtKeychain is a cross-platform Qt library for securely storing passwords and secrets using platform-native keychain services. It provides a unified QKeychain::Job API (ReadPasswordJob, WritePasswordJob, DeletePasswordJob) that delegates to the appropriate backend: macOS/iOS Keychain, Windows Credential Store (or CryptProtectData), Linux via KWallet, libsecret, or GNOME Keyring, Android Keystore, Haiku's KeyStore, and a WebAssembly bridge using the Credential Management API. The library is primarily a thin abstraction layer with clean separation of platform concerns, an internal job queue for serialization, and a fallback mechanism to store data in plaintext via QSettings when no secure backend is available. It supports Qt 5 and Qt 6, requires C++11/17, and bundles translation files for several languages.