AirLyrics

AirLyrics displays song lyrics on Android in a floating window that sits above whatever else is on screen. Rather than occupying its own full-screen view, the text stays visible while a music player, a browser, or a messaging app holds the foreground, which makes it usable for reading along during playback without switching back and forth between apps.

The lyrics are synced, meaning lines advance in step with the position of the track being played instead of being shown as one static block of text. That timing behaviour is the difference between this and a plain lyrics viewer, and it depends on the app being able to follow the playback state of whatever is producing the audio.

AndSi publishes AirLyrics under the MIT licence. It is an Android-only project, and the overlay approach means it relies on the system permission that allows drawing over other applications.