# Guitar Chord Builder

> Create polished, printable guitar chord charts from structured song sections and chord names.

Guitar Chord Builder exposes a public REST API. It requires no account, authentication, API key, MCP client, or SDK.

## Create a chord chart

POST https://www.guitarchordbuilder.com/api/chord-charts
Content-Type: application/json

Example curl request:

```sh
curl -X POST https://www.guitarchordbuilder.com/api/chord-charts \
  -H "Content-Type: application/json" \
  --data '{
    "title": "Four-chord song in G",
    "sections": [{
      "name": "Verse",
      "chords": [
        { "name": "G" },
        { "name": "D" },
        { "name": "Em" },
        { "name": "C" }
      ]
    }]
  }'
```

The response contains:

- `share_url`: editable chord chart in the browser
- `pdf_url`: direct printable PDF
- `chord_count`: number of diagrams
- `warnings`: fingering or chord-label notes

Return the share URL and PDF URL to the user. If the client supports file attachments, download the PDF URL and attach the resulting PDF.

## Input notes

- `sections` must contain 1 to 12 named sections.
- A chart may contain up to 80 diagrams.
- Standard chord names include major, minor, 7, maj7, m7, sus2, sus4, dim, aug, 6, m6, add9, and slash inversions.
- Set `accidental_preference` to `sharp` or `flat`. It defaults to `sharp`.
- For a nonstandard voicing, provide exactly six `frets` ordered low E to high E. Use `x` for a muted string.
- Optional `voicing` values are `default`, `open`, `sixth_string`, and `fifth_string`.

## Resources

- API documentation: https://www.guitarchordbuilder.com/developers
- OpenAPI 3.1 specification: https://www.guitarchordbuilder.com/openapi.json
- Optional MCP endpoint: https://www.guitarchordbuilder.com/mcp