YouTube Music, native and fast.
Your Home, Library, playlists and lyrics, in a small app that starts songs almost the moment you ask.

On a computer, YouTube Music is a web page. YTFast (YouTube Music Fast) is the same YouTube Music as a native app, built in the spirit of Spotifast: every screen laid out as YouTube Music lays it out, without the browser underneath. It is free, for YouTube Music Premium accounts, on Mac (Apple Silicon) and Windows.

Why it feels fast

• Ready before you click. Rest the pointer on a song for a moment and YTFast finds it ahead, so a click starts it almost at once. The top search result is found ahead too.
• Plays while it downloads. A song starts from its first moments while the rest arrives, and the next song is made ready while this one plays.
• No web page inside. YTFast is its own program, written in Rust. It opens quickly, scrolls smoothly, and keeps playing while minimised.
• Light. Paused, it uses 0% of the processor, and it is built to stay under 200 MB of memory (about 120 MB, measured with the demo).

Everything you know from YouTube Music

• Home, Explore and your Library, with your playlists, albums, artists and songs, measured one to one against music.youtube.com.
• Search as you type, with suggestions, pictures, past searches and YouTube Music's own filters.
• The player page: the cover beside Up next (drag songs into any order), lyrics that light word by word as they are sung, and Related. Translate shows each line in English, and in Latin letters for Japanese, Korean, Hindi and other scripts.
• Music videos: the player page's Song and Video switch plays your queue's songs as their music videos, joining each at the same music and keeping the lyrics in time.
• Your account, live: likes, playlists, saves and subscriptions go straight to YouTube Music, and every song you play reaches your History, so your recommendations keep learning.
• YouTube Music's keyboard shortcuts (press ? to see them), your keyboard's media keys, and the computer's own media controls.
• Updates itself: new versions download in the background and install when you restart.

Three looks

Choose in Settings: YouTube Music's own look (the default), Premium (charcoal and glass, with the playing song's colours behind it), or Dynamic Background (the cover's colours, moving while it plays, with large lyrics).

Get it

1. Sign in to music.youtube.com in your browser with your Premium account. On Windows, use Firefox (Chrome, Edge and Brave lock their sign-in away from other programs). On a Mac, Chrome, Firefox, Edge, Brave or Safari.
2. Download from the newest release: YTFast.exe for Windows (64-bit) or YTFast.dmg for a Mac with Apple Silicon (M1 or newer).
3. Open it and choose that browser. The first time, YTFast downloads two helpers (yt-dlp and Deno, about 250 MB) and gets ready in a minute or two. After that it signs in by itself.

YTFast is not signed with a paid certificate, so Windows says "Windows protected your PC" (click More info, then Run anyway) and a Mac asks you to allow it once in System Settings, Privacy & Security. The full guide, with every step and what to do if something goes wrong: How to run YTFast.

Want to look around first? Start it with --demo for made-up music, with no account and no sign-in.

YTFast is young and changes often. It is used every day on Windows; the Mac build comes from the same code but has been tried less.

Your account and your data

• YTFast reads only YouTube's sign-in from your browser; every other site's is dropped the moment it is read. The copy stays on your computer in a private folder, is deleted when YTFast closes, and is only ever sent to YouTube.
• Songs are found the way the website finds them, and sometimes through yt-dlp. yt-dlp's makers warn that an account used with it can be banned. YTFast only asks for what a listener does (the song playing and the next few), never bulk downloads, but the risk is not zero.
• Never paste your browser's cookies or a cookies.txt file into any chat.

How it works

• Your sign-in comes from your web browser, and is read again by itself whenever YouTube stops accepting the copy YTFast has.
• Your music (Home, Library, search) comes from the same internal API music.youtube.com uses. There is no official YouTube Music API.
• The audio of each song is found the way the website finds it, with yt-dlp's challenge solver kept running in Deno, and plays while it downloads. If that fails, yt-dlp itself finds the song. YTFast downloads yt-dlp and Deno and checks both against their published fingerprints.
• Lyrics come from Musixmatch (timed word by word), YouTube Music or LRCLIB (a free lyrics database). The next song's lyrics load while the current one plays. Translations come from Musixmatch (written by people) or Google Translate.
• Videos are YouTube's own, decoded by YTFast itself (H.264, up to 720p), and only while the player page shows them.
• Playing happens in YTFast itself, through the same audio code as Spotifast: it follows your headphones and uses no processor while paused.

For developers and AI assistants

Start with AGENTS.md: what YTFast is, how the code is laid out, its rules, and what has been tested. Build and test:

cargo test --workspace
cargo run -p ytfast              # the app
cargo run -p ytfast -- --demo    # the app with made-up music, no account
cargo run -p ytfast-check        # the step 0 check

Linux needs libasound2-dev for the audio library. The plan and its risks: docs/plan.md. Making a release: docs/releasing.md.

Credits

YTFast builds on fastframe and learns from Spotifast (both MIT, by Carmine Paolino), ytmusicapi (MIT), Kaset (MIT) and yt-dlp (Unlicense). Its lyrics follow the style of Better Lyrics' Even Better Lyrics Plus theme (recreated without its code), and its Dynamic Background look recreates chengggit's Dynamic Background theme for Better Lyrics (MIT). Lyrics come partly from LRCLIB, and from Musixmatch through ThetaDev's musixmatch-inofficial (MIT). Music videos are decoded by rusty_h264 (BSD 2-Clause), with SIMD kernels from OpenH264 (BSD 2-Clause). Icons are Google's Material Symbols (Apache 2.0) and Lucide (ISC); the fonts are Roboto and Inter (SIL Open Font License). Their licence texts, and those of the Rust libraries YTFast is built from, are in THIRD-PARTY-NOTICES.txt, which comes with every download.

YTFast is an independent project, not affiliated with YouTube or Google. YouTube and YouTube Music are trademarks of Google LLC. Using unofficial apps is against YouTube's terms of service; see the risks in docs/plan.md.