Short answers, checked against the app rather than written from memory.
What do I need to run it?
Android 12 or newer. There is no iOS version and none is planned.
What files does it play?
Whatever your phone can decode: MP3, AAC and M4A, FLAC, Ogg Vorbis, Opus and WAV among them. Playback is built on Media3, the same engine most Android players use, so if another app on your phone can play a file this one generally can too.
Does it need an internet connection?
No. Your music, library, playlists and settings are all on the device and the app works fully with the network off. Two optional features do reach out, and they are covered in the next answer.
What does it send, and when?
Artist photos and artist descriptions are on by default. When you open an artist for the first time the app sends that artist's name, and nothing else, to Deezer for a photo and to Wikipedia for a short biography. Both are limited to Wi-Fi by default, so neither spends mobile data unless you let it.
Nothing about what you listen to, or when, is ever sent. There is no analytics, no crash reporting and no advertising code in the app. To switch the lookups off entirely, go toSettings → Artists; with them off the app makes no network requests at all. The privacy policy is the long version.
How does it decide what my library is?
You do. There is a real folder tree with include and exclude rules, so a podcast folder, a ringtones folder or a directory of voice memos can be kept out of the library without moving any files. Sorting takes more than one key at a time, and folders can keep their own sort.
Can it read my existing playlists?
Yes. Playlists are ordinary .m3u files in the sharedMusic/Playlists/ folder rather than rows in a database only this app can read, and an existing .m3u or .m3u8 from anywhere on the device can be imported. Nothing is locked in: uninstall the app and the playlists are still files.
Where do lyrics come from?
Out of your own files: the lyrics tag the file already carries, including synced LRC, which is highlighted line by line as the song plays. The app does not fetch lyrics from a service.
Can I fix my tags?
Yes: titles, artists, albums and artwork, one track at a time or a whole album at once. Edits are written into the files themselves, so they travel with your music.
What does it cost?
It is free, with no ads and no account. A one-time paid unlock for some advanced features is planned later, around $5, bought once, never a subscription.
Two promises attached to that, and they are the reason it is written down here rather than left vague: nothing that is free today will be moved behind the paywall, and everyone who installs during early access is grandfathered into the paid tier permanently.
Is it open source?
No. The app is closed source, and it uses a lot of other people's open source, which is credited on the licences page.
Something is broken, or missing.
Mail [email protected]. Bug reports are more useful with the phone model and Android version in them.