ykDroid is a USB and NFC driver for Android that exposes the challenge-response feature of YubiKeys for use by other Android apps. Both USB and NFC (YubiKey NEO required for NFC) are supported on compatible devices.
Apps supporting it include e.g. Keepass2Android and ykpass.
Although APK downloads are available below to give you the choice, you should be aware that by installing that way you will not receive update notifications and it's a less secure way to download. We recommend that you install the F-Droid client and use that.Download F-Droid