Linksets

Linkset Responses¶

GTIN1 returns linkset responses for GTIN (AI 01) URIs, conformant with GS1 Digital Link and IETF RFC 9264. These responses allow clients to programmatically discover all available resources associated with a product without parsing HTML.

The linkset implementation has been validated against GS1 and IETF conformance suites.

Content Negotiation¶

Request a linkset by setting the Accept header or using the linkType query parameter:

Accept: application/linkset+json returns the JSON linkset representation
?linkType=linkset returns the linkset regardless of the Accept header

Non-linkset responses (HTML redirects) include Link HTTP headers pointing to the linkset for discoverability.

Anchor¶

The linkset anchor for AI 01 is the canonical Digital Link URI: https://gtin1.com/01/{gtin14}.

Relation Vocabulary¶

Link relation types in the linkset use full GS1 vocabulary URLs for GS1 link types (e.g., https://gs1.org/voc/pip) and short names for IANA relations (e.g., describedby, canonical).

GTIN1 includes relations based on the product's available data:

Relation	Description	Included when
`https://gs1.org/voc/pip`	Product information page	Always
`https://gs1.org/voc/defaultLink`	Default link (GS1 conformance)	Always
`canonical`	Canonical Digital Link URI	Always
`describedby`	JSON-LD structured data	Always
`https://gs1.org/voc/brandHomepageClinical`	Brand homepage	Brand has a website
`https://gs1.org/voc/instructions`	Usage instructions	Trade item has instructions
`https://gs1.org/voc/recallStatus`	Recall status	Product has an active recall
`https://gs1.org/voc/certificationInfo`	Certifications	Product has certifications
`https://gs1.org/voc/allergenInfo`	Allergen information	Product has allergen data
`https://gs1.org/voc/traceability`	Traceability data	Product is on the FSMA 204 Food Traceability List

Example: `application/linkset+json` for AI 01¶

{
  "linkset": [
    {
      "anchor": "https://gtin1.com/01/00785034739064",
      "https://gs1.org/voc/pip": [
        {
          "href": "https://gtin1.com/catalog/ti/abc123xyz/",
          "title": "Organic Olive Oil 500ml"
        }
      ],
      "https://gs1.org/voc/defaultLink": [
        {
          "href": "https://gtin1.com/catalog/ti/abc123xyz/",
          "title": "Organic Olive Oil 500ml"
        }
      ],
      "canonical": [
        {
          "href": "https://gtin1.com/01/00785034739064",
          "title": "Canonical URI"
        }
      ],
      "describedby": [
        {
          "href": "https://gtin1.com/catalog/ti/abc123xyz/jsonld/",
          "type": "application/ld+json",
          "title": "JSON-LD Structured Data"
        }
      ],
      "https://gs1.org/voc/certificationInfo": [
        {
          "href": "https://gtin1.com/catalog/ti/abc123xyz/#certifications",
          "title": "Certifications"
        }
      ]
    }
  ]
}

Each relation key maps to an array of link targets. Each target includes href and may include type, title, and hreflang attributes.