Public Datasets

These are downloadable, versioned snapshots of the core piano.org reference data: the notes, pitch classes, and interval structure of every chord and scale in all 18 keys. Every record is derived deterministically from the piano.org theory kernel (root plus interval plus letter-offset spelling), the same single source of truth behind the reference pages, so the files are reproducible and human-verifiable rather than hand-authored.

The format is newline-delimited JSON (JSONL): one self-contained JSON object per line. You may use these datasets, with attribution to piano.org. See how this site is made for provenance and terms.

Available datasets

Record fields

• id:stable identifier, e.g. chord:major:c.
• kind:chord or scale.
• name, root, quality:the human-readable name and its parts.
• notes:ordered note spelling (with sharps/flats), no octaves.
• pitch_classes:pitch classes 0–11 for each note.
• intervals_semitones:semitone offsets from the root.
• url:the canonical reference page for that entry.

Scope and versioning

Version 1 covers the canonical chord and scale catalogs across the 18 keys, limited to spellings the kernel derives unambiguously. A small number of symmetric scales (whole-tone, diminished, bebop, chromatic) and rare triple-accidental spellings are intentionally out of v1; their reference pages remain the source of truth. Datasets are versioned in the filename (-v1); a new revision ships as a new file so existing citations never break.