Musical Key Detection API for Harmonic Workflows

What Pulse returns

key root
major/minor scale estimate
key confidence
job status and selected-tool cost details

Example workflow

Ask Pulse for a free estimate, confirm the user has permission or lawful access, run key detection, then use the result as musical context rather than a guarantee; ambiguous, atonal, noisy, or short audio may need human verification.

From a sound to your own song

Choose a kit with pitched parts in the same documented key, add your own melody, then check your finished track for harmonic context. Pulse Open Loops offers free original CC0 synthesis kits: drums, bass, chords and percussion. Play the parts together, mute roles and download four WAVs for your DAW, without an account. Automated checks are not listening review.

Build and export your track, then use a public downloadable audio link for a free Pulse estimate. Submit only audio you have rights, permission, lawful access or another legal basis to process. Analysis uses an eligible one-track trial, Checkout or banked tokens.

Pricing and estimates

Estimates are free before paid analysis. One analysis up to 5 minutes. URL only; BPM, key and waveform. Up to two queued attempts if the first fails. Rights, permission, lawful access, or another legal basis required. Pulse prices selected tools by audio duration using the same tool multipliers exposed by /tools: waveform 0.06 tokens/second, BPM 0.1 tokens/second, and key 0.1 tokens/second. The current token price is $0.005.

60 second key example6 tokens$0.03

3 minute full v1.0 suite47 tokens$0.24

Cached resultMay cost less$0.001 current cache-hit price

Examples are estimates. Review the returned estimate before payment or API-key analysis. Final charges depend on measured duration, completed tools, cached analysis and checkout-path constraints.

Result guidance

For audio of at least 30 seconds whose type is unconfirmed, strong BPM or key readings may be shown as Audio detection candidate with Review manually. These unverified tags require a listening check; detector confidence is not a calibrated probability of accuracy.

Key detection is harmonic context, not a guarantee. Low-confidence, atonal, noisy, modulating, or very short audio should be checked by ear before committing catalog tags or DJ transitions.

For DJ planning, convert the detected key into your preferred harmonic-mixing notation, including Camelot-compatible labels, then use adjacent and relative keys as candidates rather than rules.

Pulse helps discovery and utility by making analysis explicit: result, confidence, selected tools, and job status. Human listening judgment remains the final check for release, performance, or catalog commitments.

Rights-aware analysis boundary

Pulse is designed for audio the user has rights, permission, lawful access, or another legal basis to submit. Agents and apps should confirm that before analysis. Pulse does not provide transcription, stem separation, mastering, loudness correction, chord transcription, or track structure segmentation in v1.0.

Pulse is designed to make audio analysis auditable. Each analysis flow should make clear which URL was submitted, which tools were selected, what the estimate was, when rights confirmation was given, and whether the job completed, partially completed, failed, or expired.