BPM & Key Finder for Bandcamp — Crate

Dig Bandcamp like a DJ: this bpm and key finder shows tempo, Camelot key and a deck-style waveform for every track. Runs locally.

Crate turns Bandcamp into a digging tool for DJs. Play any track and a bpm and key finder draws a three-band waveform, the tempo and the Camelot key right under the player, so you can tell in two seconds whether a record is worth your money. Everything is analysed on your own machine. Nothing is uploaded. 🎧 Why a DJ needs more than a play button Bandcamp gives you a play button and a stopwatch. A DJ digging through a tag page or a label catalogue needs the same information a club deck shows: where the intro ends, where the drop lands, how fast the track is and which key it is in. Crate adds exactly that, on every Bandcamp page where music plays, without leaving the page. 🚀 How the bpm and key finder works 1. Open any album, tag page, feed or discover page on Bandcamp. 2. Press play. Crate reads the same preview stream the Bandcamp player is already loading. 3. Within about a second and a half the waveform starts drawing; the bpm and the song key land in three. No extra button, no copy and paste, no account. The track you play is the track you see. 🌊 What appears under every track 🔹 A waveform in three bands. Bass, mids and highs are drawn the way a club CDJ draws them: intros, breakdowns and drops read as shapes, a hi-hat stays a spike and a bassline stays a mass. 🔹 Tempo detector. The bpm is read from the low-frequency pulse and brought into the DJ range of 90 to 180 bpm, so a 128 bpm house track is not reported as 64. 🔹 Music key detection in Camelot notation. The key finder shows 7B · F instead of leaving you to translate. When the result is uncertain, Crate marks it with a question mark rather than pretending to be sure. 🔹 A grid that counts bars, not seconds. Lines follow the detected tempo and every eighth bar is brighter, the way DJs count. 🔹 Transport that stays out of the way. Click the waveform to seek, arrows skip and seek, space pauses. The strip turns amber for the last thirty seconds. 🔒 Private by design ➤ The audio never leaves your browser. Waveform, bpm and key detection run in a background document inside the extension. ➤ There is no server and no account. Results are cached locally so a track you already heard is instant. ➤ Crate only analyses tracks you actually play. It never crawls albums or downloads music behind your back. ➤ The only data sent anywhere is an anonymous usage counter that you can switch off in one click. It never contains track titles, artists or Bandcamp URLs. 🎛️ Built for the way DJs dig ▸ Keyboard digging: ↑ ↓ jump to the previous or next track, ← → skip 5 seconds, space pauses. Run through a whole release without touching the mouse. ▸ Tag pages and discover: listen through a tag, and every track that starts playing gets a waveform and a bpm. Compare keys across a whole page before you buy a single record. ▸ Label catalogues: open release after release. Every track you have already played comes back instantly from the local cache, waveform, bpm and key included. ▸ Harmonic mixing: the Camelot key under each track makes it easy to spot which new records sit next to what is already in your crate. ▸ Long mixes and radio shows: analysis is streamed, so a three-hour mix gets a readable overview instead of a wall of identical spikes. 📐 Drawn like an instrument • Different envelope timings per band: 120 ms on the bass, 30 ms on the highs. That is what separates a deck waveform from an oscilloscope. • Resolution adapts to track length, from 200 columns per second on a club track to 20 on a long mix, and every sample still goes through the filters. • Peaks are accented above the body of the waveform rather than stretching a column to full height, so dense percussive tracks stay readable. 💡 Who uses Crate 1️⃣ Club and radio DJs who buy on Bandcamp and want a bpm finder while they browse, not after the download. 2️⃣ Vinyl and digital collectors who sort by key and tempo before adding a record to the cart. 3️⃣ Producers and label owners who check how a release reads as a set of shapes, not only as a list of titles. 4️⃣ Anyone learning to DJ who wants to see what a breakdown, a drop and a 4/4 pulse look like on a real track. ❓ Frequently asked questions 📌 Does Crate upload my listening data anywhere? 💡 No. There is no server. The waveform, the tempo and the key are computed in your browser and the results stay there. 📌 Does it download music? 💡 It reads the same preview stream the Bandcamp player uses, keeps it in memory long enough to draw the waveform, and drops it. 📌 Can Crate analyse my own audio files or tracks outside Bandcamp? 💡 No. Crate works on Bandcamp pages only and does not analyse files from your computer or tracks on other sites. 📌 Does the bandcamp bpm finder work outside album pages? 💡 Yes. Tag pages, feeds, discover and artist pages too. Anywhere music plays on Bandcamp, the strip comes up. 📌 How accurate are the tempo and the key? 💡 Tempo is reliable on four-to-the-floor music and can land on half or double time on odd rhythms. The song key is detected from the preview; when it is a guess, Crate shows a question mark instead of a confident wrong answer. 📌 Which Chrome version do I need? 💡 Chrome 116 or newer. The decoder runs in a worker inside the extension, so older browsers are not supported. 📌 It stopped drawing waveforms. What do I do? 💡 Reload the Bandcamp tab. Preview links on Bandcamp expire after a few hours, and a fresh page brings a fresh link. 🎚️ Dig through Bandcamp like a DJ, not a listener. Add Crate to Chrome, open an album, press play, and let the bpm & key finder show you the track before you buy it.