Music Theory
music-theory.x402tookit.com · 10 paid endpoints · listed 2026-11-02
Transpose a chord progression by semitones or from one key to another, with spelling that fits the target key.
Paid endpoints
| Method | Endpoint | Price | Networks |
|---|---|---|---|
| GET | music-theory.x402tookit.com/chord Spell a chord from its symbol (Cmaj7, F#m7b5, G7b9, Dsus4, C/E): notes, intervals, semitones and MIDI numbers. | $0.02 | Polygon, Arbitrum, Base, Solana |
| GET | music-theory.x402tookit.com/chord-name Name a chord from its notes (C E G Bb, A C E G): best name, inversion and alternative names; first note is the bass. | $0.02 | Polygon, Arbitrum, Base, Solana |
| GET | music-theory.x402tookit.com/freq-note Frequency in Hz to the nearest note, MIDI number and offset in cents; adjustable A4 reference; tuner-style result. | $0.02 | Polygon, Arbitrum, Base, Solana |
| GET | music-theory.x402tookit.com/interval Interval between two notes (quality, number, semitones) or the note a given interval above or below a note. | $0.02 | Polygon, Arbitrum, Base, Solana |
| GET | music-theory.x402tookit.com/key-signature Key signature (sharps or flats), circle-of-fifths neighbours, relative and parallel keys for any major or minor key. | $0.02 | Polygon, Arbitrum, Base, Solana |
| GET | music-theory.x402tookit.com/note-freq Note name (C#4, Bb3) or MIDI number to MIDI, frequency in Hz and wavelength, with adjustable A4 reference pitch. | $0.02 | Polygon, Arbitrum, Base, Solana |
| GET | music-theory.x402tookit.com/roman-numerals Roman numeral analysis of a chord progression in a key: numerals, inversions, borrowed chords, secondary dominants. | $0.02 | Polygon, Arbitrum, Base, Solana |
| GET | music-theory.x402tookit.com/scale Spell a scale or mode on any root: major, minor, modes, harmonic and melodic minor, pentatonic, blues, whole tone. | $0.02 | Polygon, Arbitrum, Base, Solana |
| GET | music-theory.x402tookit.com/tempo BPM to milliseconds for note values, dotted and triplet delay times; or average tap intervals into a steady BPM. | $0.02 | Polygon, Arbitrum, Base, Solana |
| GET | music-theory.x402tookit.com/transpose Transpose a chord progression by semitones or from one key to another, with spelling that fits the target key. | $0.02 | Polygon, Arbitrum, Base, Solana |
Latest checks
| When | Endpoint | HTTP | ms | Result |
|---|---|---|---|---|
| Not checked yet. | ||||
Income on Base (7 days)
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