What SignalKey is
SignalKey is a free, no-signup AI music analysis platform. Drop any audio file and we extract BPM, key, Camelot code, chord progression, stems, MIDI, LUFS and a full mix-clinic report — in one upload.
You can use a single-purpose tool page if you came for one specific answer, or open the Studio for the full producer-grade workbench.
Why we built it
Music analysis tools used to be expensive, fragmented, or hide their best features behind paywalls. We thought a producer or DJ asking "what BPM is this?" shouldn't have to sign up, pay, or wait for a 5-minute upload.
SignalKey runs the same models the pro tools use — Spotify Basic Pitch for melody-to-MIDI, librosa-grade chroma analysis for keys, BS.1770-4 for loudness, Demucs v4 for stems — and gives them away free, with sane daily caps so the GPU bill stays bounded.
How we make money
Two streams, both deliberately quiet.
Studio subscriptions ($19/mo) — the unified workbench, 24-bit WAV stems, saved sessions, batch upload, API access and 50× higher daily caps. Power users who need real throughput pay for it; everyone else gets the tools free.
One quiet ad on long-form learning pages— the glossary, charts, song database, audience guides and competitor comparisons each carry a single “Sponsored” unit. Tool pages and the Studio workbench are 100% ad-free because video ads would corrupt the task you came for.
What we don't do
- We don't store your audio files. Analysis is in-flight; files are deleted in minutes.
- We don't require accounts.
- We don't sell your data.
- We don't train AI models on your uploads.
- We don't watermark output. Stems and MIDI are clean, full-fidelity.
The team
A small group of producers, DJs and engineers who got tired of the status quo. We ship updates frequently — see the changelog and public roadmap.
Get in touch
Use the contact form, the API if you're a developer, or peek at press kit for media assets.