Yubico offers two great user experiences on Android employing a simple tap for NFC or a physical connection with USB.
Authentication via NFC is supported by the YubiKey 5 NFC.
Authentication via physical connection is supported by the NFC keys named above and all of the other YubiKeys with the USB connector (see the YubiKey support on Android article for a list of these.
Yubico Android SDK (YubiKit for Android) is an Android library provided by Yubico to enable interaction between YubiKeys and Android devices. The library supports NFC-enabled and USB YubiKeys.
Documentation for the SDK, such as instructions on adding it to your project and getting started, is available on GitHub.
JavaDoc APIs for the various modules can be found here.
If you run into any issues during the development process, please fill out a developer support ticket and our team will be happy to assist you.