National Drug Code.
Three 10-digit layouts, the 11-digit billing canonicalization, "check": "none", and the GTIN embedding behind the "3" prefix.
Ten digits, three readings — blown out in parallel.
Every plausible split, side by side: the layout is data from the labeler code. The 11-digit billing form zero-pads to 5-4-2: 00002-3227-30.
NDC 0002-3227-30
check none — the scheme defines no check digit
"check": "none" — the NDC carries no check digitThe row.
| scheme | ndc |
|---|---|
| grammar | 10 digits in three layouts — 4-4-2, 5-3-2, 5-4-1 (labeler–product–package); the layout is data from the labeler code, not guessable from the digits alone. |
| check digit | None — structurally validated only; the output says "check": "none". |
| canonical form | The 11-digit 5-4-2 form (the billing convention), zero-padded per segment. |
| symbologies | The US drug UPC/GTIN embeds the NDC behind the “3” prefix; serialized DSCSA packs carry GS1 DataMatrix with AI 01+21+17+10 |
| enrichment | openFDA drug/ndc (CC0), updated daily, inside the provenance envelope |
| join rule | GTIN-14/UPC embedding extraction returns separate wrapper-vs-contents verdicts: the GTIN can pass mod-10 while the embedded NDC is the real identity. |
| pinned digest | ndc sha256:c4fa97fcfac0ca834c750b6700e3bcf5cba3631f2f906217d9b9360b955108fa |
| as data | /schemes/ndc.json |
In practice.
The NDC is the registry's standing argument for typed verdict labels: a vocabulary that can only say pass or fail has no answer for a scheme with no check digit. The closed label set — mod10 pass · iso3779 mod11 pass · none · best-effort — is output contract, not prose.
On the blog.
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NDC: the identifier with no check digit, and what validation means without one
The National Drug Code is ten digits in three segments and carries no check digit at all — so "valid" can only ever mean structurally parseable plus present in the registry. The NDC is the scheme that forces a resolver to be honest about validation tiers, and the honesty generalizes.
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Pharma already lives in 2027: DSCSA as the serialization precedent
Every US prescription-drug package already carries a GS1 DataMatrix with GTIN, serial, lot, and expiry under DSCSA — the one US vertical where serialized 2D is universal at the unit level. Parsed live, with the NDC-inside-GTIN embedding shown, and the lessons a cross-vertical CTO can actually reuse.
Get an API key.
The local verbs run from npx barcoding.dev today with no key. A key opens the network half of the verb set.