ToolVet

Music Theory

10 x402 APIs served from music-theory.x402tookit.com

Every listing from Music Theory that ToolVet tracks. Each one is called on a schedule without paying and scored out of 100.

At a glance

Listings
10 x402 APIs
Passing at the latest check
7 of 10
Uptime, 30 days
58.5% on average across 10 listings
Price
$0.02 per call
Trust score
33 to 63, median 59
Paying wallets, 30 days
No usage data
Verified owner
None
Security findings
None found
Listed since
20 Oct 2026

No usage data. The x402 Bazaar reports paying wallets for the x402 APIs it lists; MCP servers and APIs submitted directly have none.

All 10 listings

Ranked by trust score.

  • 63trust
    Key SignatureMusic Theory

    Key signature (sharps or flats), circle-of-fifths neighbours, relative and parallel keys for any major or minor key.

    x402 APIOther
    $0.02per call on Polygon
    70.6% uptime, 528 msPassing, checked 8 h ago
  • 61trust
    Roman NumeralsMusic Theory

    Roman numeral analysis of a chord progression in a key: numerals, inversions, borrowed chords, secondary dominants.

    x402 APIOther
    $0.02per call on Polygon
    64.3% uptime, 525 msPassing, checked 4 h ago
  • 60trust
    ScaleMusic Theory

    Spell a scale or mode on any root: major, minor, modes, harmonic and melodic minor, pentatonic, blues, whole tone.

    x402 APIOther
    $0.02per call on Polygon
    60.0% uptime, 509 msPassing, checked 4 h ago
  • 59trust
    TransposeMusic Theory

    Transpose a chord progression by semitones or from one key to another, with spelling that fits the target key.

    x402 APIOther
    $0.02per call on Polygon
    56.3% uptime, 525 msPassing, checked 6 h ago
  • 59trust
    IntervalMusic Theory

    Interval between two notes (quality, number, semitones) or the note a given interval above or below a note.

    x402 APIOther
    $0.02per call on Polygon
    56.3% uptime, 559 msPassing, checked 2 h ago
  • 59trust
    Freq NoteMusic Theory

    Frequency in Hz to the nearest note, MIDI number and offset in cents; adjustable A4 reference; tuner-style result.

    x402 APIOther
    $0.02per call on Polygon
    56.3% uptime, 507 msPassing, checked 2 h ago
  • 58trust
    ChordMusic Theory

    Spell a chord from its symbol (Cmaj7, F#m7b5, G7b9, Dsus4, C/E): notes, intervals, semitones and MIDI numbers.

    x402 APIOther
    $0.02per call on Polygon
    53.3% uptime, 502 msPassing, checked 9 h ago
  • 34trust
    TempoMusic Theory

    BPM to milliseconds for note values, dotted and triplet delay times; or average tap intervals into a steady BPM.

    x402 APIOther
    $0.02per call on Polygon
    57.9% uptime, 559 msFailing, checked 27 h ago
  • 34trust
    Chord NameMusic Theory

    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.

    x402 APIOther
    $0.02per call on Polygon
    56.3% uptime, 520 msFailing, checked 25 h ago
  • 33trust
    Note FreqMusic Theory

    Note name (C#4, Bb3) or MIDI number to MIDI, frequency in Hz and wavelength, with adjustable A4 reference pitch.

    x402 APIOther
    $0.02per call on Polygon
    53.9% uptime, 446 msFailing, checked 21 h ago

Watch these listings in one feed

How these numbers are made

Each listing is called on a schedule without paying. Listings with usage or a verified owner are checked about every 30 minutes, others about every 6 hours. Uptime is the share of passing checks over 30 days, averaged across this provider's listings. Trust scores follow the published method. The figures on this page can be a few minutes behind the latest checks, and listings hidden after review aren't counted.