A single public endpoint

No key, no sign-up, read-only. This site's lookup page calls exactly this endpoint — there is no other.

GET https://filament.yumi-lab.com/v1/public/spool?lot=20250914001234X001&ean=6975337080015

The response

{
  "produit_nom": "PLA Ultra Speed 1kg",
  "couleur_nom": "Steel Blue",
  "hex_officiel": "627EAC",
  "hex_mesure": "627EAC",
  "td": 1.9,
  "qc_valide": true
}

Field	What it means
`produit_nom`	The product name, resolved from the barcode. May be missing.
`couleur_nom`	The reference colour name. Missing until a reference is recorded.
`hex_officiel`	The product's reference colour. Missing until a reference is recorded.
`hex_mesure`	The colour measured ON THIS BATCH. Always present.
`td`	The transmission measured on this batch. Always present.
`qc_valide`	False until an operator has confirmed the measurement.

Refusals

404 not_found: The batch + barcode pair is unknown. The answer is IDENTICAL whether the batch does not exist, the barcode does not match, or the product is unknown: telling these apart would reveal which batches exist.
429 too_many_requests: Too many requests from one address. The retry header says how many seconds to wait.

What this registry does not tell you

The response carries NO date: not manufacturing, measurement, import, nor any increasing identifier. The batch number itself does contain its manufacturing date — that cannot be removed, it is printed on the label. So this is not a protection: it is hygiene, stated plainly rather than promised.

Colour difference is computed as ΔE00 (CIEDE2000) from a HEX code. This is an APPROXIMATION: the colorimeter's illuminant and observer are unknown. Enough to detect a drift, not enough to settle a dispute to the decimal.