Instrument catalog

The catalog is a read-only API over the instruments Mr Charles knows: a taxonomy of instrument types (from grand pianos to triangles, in several languages, with an openly licensed picture each), models by manufacturer with specifications, identifiers (GTIN/UPC/EAN, MPN, SKU), images and variants (sizes, finishes, each with its own barcode).

All paths are under https://api.mrcharles.app/api/v1/instruments (api-pre.mrcharles.app in the sandbox). Responses follow the common envelope: { "success": true, "data": …, "meta": … }.

Authentication and limits

Caller	Header	Limit
Anonymous	none	120 requests per minute per IP
Shop / integration	`X-API-Key: mck_…`	the key’s own limit (default 600 per minute)

Ask developers@mrcharles.app for a key. Every response carries X-RateLimit-Limit, X-RateLimit-Remaining and X-RateLimit-Reset; a 429 includes Retry-After. An unknown or revoked key answers 401 INVALID_API_KEY / API_KEY_REVOKED.

Taxonomy

The taxonomy is a tree: category → group → family → sub-type. Every node is a family with a kind:

`kind`	Meaning	Examples
`group`	Navigation only; holds no models	Cymbals, Drum kits and sets, Guitars
`instrument`	An instrument type	Alto saxophone, Cajón, Grand piano
`set`	Several pieces sold together	Drum kit, Shell pack, Cymbal pack, Hardware pack
`component`	A piece of a set or of an instrument	Snare drum, Crash cymbal, Hi-hat stand, Mouthpiece, Pickup
`accessory`	Used with an instrument	Drumsticks, Straps, Cases, Stands
`consumable`	Wears out and is replaced	Drumheads, Strings, Reeds, Picks

Families relate to each other: component_of (a snare is a component of a drum kit), accessory_for (sticks for drums and cymbals), consumable_for (heads for snares). A relation declared on a group applies to everything beneath it, and the API resolves that for you: ask for crash-cymbal and you get the accessories declared for Cymbals.

Each family also carries an attribute schema — the specification keys shops should fill for its models (diameter, alloy, weight for cymbals; size, tip, material for sticks), inherited down the tree.

	Endpoint	Notes
GET	/taxonomy	The whole tree with `kind`, `labels`, `imageUrl`, `modelCount` and `totalModelCount` per node. Cache it; it changes rarely
GET	/categories	Ten categories with `labels` (`en`, `es`, `ca`, `fr`)
GET	/families?category=percussion&kind=component&parent=cymbals	Flat list; every filter optional. `parent=none` gives top-level families
GET	/families/{slug}	One family: `ancestors`, `children`, `components`, `partOf`, `accessories`, `consumables`, `usedWith`, `attributes` (`?include=` to pick)
GET	/families/{slug}/attributes · /components · /accessories · /consumables	The same, one list at a time

{
  "slug": "crash-cymbal",
  "kind": "component",
  "path": "cymbals/crash-cymbal",
  "labels": { "en": "Crash cymbal", "es": "Plato crash", "ca": "Plat crash", "fr": "Cymbale crash" },
  "ancestors": [{ "slug": "cymbals", "kind": "group" }],
  "partOf": [{ "slug": "drum-kit", "relation": "component_of" }, { "slug": "cymbal-pack", "relation": "component_of" }],
  "accessories": [{ "slug": "drumsticks", "via": "cymbals" }, { "slug": "drum-cases-and-bags", "via": "cymbals" }],
  "consumables": [{ "slug": "cymbal-felts-and-sleeves", "via": "cymbals" }],
  "attributes": [
    { "key": "diameter", "dataType": "number", "unit": "in", "isFilter": true, "inheritedFrom": "cymbals" },
    { "key": "alloy", "dataType": "enum", "options": ["B20", "B12", "B10", "B8", "brass", "nickel silver", "stainless steel", "other"], "isFilter": true, "inheritedFrom": "cymbals" },
    { "key": "weight", "dataType": "enum", "options": ["paper thin", "extra thin", "thin", "medium thin", "medium", "medium heavy", "heavy", "extra heavy"], "isFilter": true, "inheritedFrom": "cymbals" }
  ]
}

Show imageAttribution next to a family picture; the licence requires it for CC BY licences and it is good practice for public-domain ones.

Models

	Endpoint	Notes
GET	/search?q=&category=&family=&manufacturer=&kind=&sort=&page=&perPage=	Published models; full-text and fuzzy on name, manufacturer and aliases. `family=` includes everything under that family (`cymbals` finds crashes and rides); add `shallow=true` for the family alone. `kind=` filters by family kind; `sort=newest
GET	/search?family=crash-cymbal&spec[diameter]=18&spec[alloy]=B20	Attribute filters: `spec[key]=value` for any key in the family’s `/attributes`
GET	/{idOrSlug}	One model
GET	/{idOrSlug}?include=all	With `specifications`, `media`, `identifiers`, `variants`, `aliases` in one call (`include` takes a comma list)
GET	/{idOrSlug}/specifications · /media · /identifiers · /variants · /aliases	The same, one resource at a time
GET	/manufacturers?q= · /manufacturers/{idOrSlug}	Brands

media only lists images whose rights were checked by a person and that carry a usable licence; url may be on our origin (/instruments/image?u=…) when the manufacturer’s CDN refuses cross-site loads.

Lookup by barcode or part number

	Endpoint	Notes
GET	/lookup?gtin=810054347026	Also `upc=`, `ean=`, `barcode=` (any padded form is accepted), `mpn=`, `sku=`

{
  "instrument": { "slug": "kala-west-coast-woods-tenor-xl-ukulele", "manufacturerName": "Kala", "familySlug": "ukulele", "…": "…" },
  "identifier": { "identifierType": "upc", "value": "810054347026", "variantId": "a1f6…" }
}

identifier.variantId is set when the barcode belongs to one variant (a size or finish). 404 RESOURCE_NOT_FOUND when nothing carries the identifier.

Keeping a copy in sync

	Endpoint	Notes
GET	/changes?since=2026-10-01T00:00:00Z&page=1&perPage=100	Published and deprecated models changed at or after `since`, oldest first

Store the last updatedAt you processed and pass it back as since; overlapping by a second is fine (rows repeat, ids do not change). A model whose status is deprecated was withdrawn by the manufacturer: keep it for history, stop offering it.

Errors

Standard errors plus:

Code	Meaning
`INVALID_API_KEY`	Unknown key
`API_KEY_REVOKED`	Key revoked by an administrator
`RATE_LIMITED`	Over the limit; see `Retry-After`
`VALIDATION_ERROR`	Missing or malformed `since`, or no identifier given to `/lookup`

Where the data comes from

Manufacturers’ own catalogs (their stores’ public product data), reviewed before publication; instrument types from Wikidata and Wikimedia Commons. Prices are not part of the catalog.