BeatKey

The BPM, key and time signature of what you play on YouTube, Spotify, SoundCloud and more. Change the tempo, keep the pitch.

BeatKey shows the tempo, time signature and key of the music you play, in a small window you can drag anywhere. It sits in the player bar on seven music sites, YouTube and SoundCloud among them (the screenshots list them all); on Spotify and other sites it opens at a click on its icon. Type a BPM and the track plays at that speed, pitch unchanged. Made for DJs and producers: • BPM to two decimals. An AI beat tracker (Beat This!) finds every beat, and the tempo comes from the whole song, decided by the kick and counted as DJ software counts it (a half-time intro reads 120, not 60). It holds steady through breakdowns and build-ups. • The key, in Open Key notation as Traktor shows it (hover for its name and Camelot code). On the GiantSteps EDM test set it gets the key exactly right for 69% of tracks, and right or a harmonic neighbour for 90%. • The time signature: 4/4, 3/4… • Tempo change: type a BPM and press Enter. The track stays exactly on it, pitch unchanged, as the reading sharpens; one click goes back to the original speed. • No guessing: until a clear beat plays it says "Analyzing…" instead of a number, and the decimals are dimmed while they settle. • In the player bar it sits next to the volume and hides with the site's own buttons. Drag it out by its grip and it floats where you drop it, and opens there the next time; drop it back on the player, or close and reopen it, to put it back in the bar. In a narrow browser it leaves out what matters least, then hides; the toolbar badge keeps showing the tempo. Where the audio is protected, or a preview streams from another domain, Chrome lets an extension hear a tab only after you click its icon. One click (or Alt+Shift+B) opens the window and starts listening to that tab, until you close the window or the tab. Private: the sound is analysed on your computer. Nothing is recorded or sent anywhere; the only thing kept is where you left the window on each site. No account, no tracking. How it works: it listens to a copy of the page's sound (what you hear doesn't change), runs two small AI models in a hidden extension page, and shows the results in the player or in its window. YouTube ads are ignored. BeatKey is not affiliated with any of the music sites it works on.