iso6523Code

iso6523Code · Recommended

Appears in

Organization

What is it?

ISO 6523 is an international standard that defines a framework for identifying organizations using a structured code format. It pairs an ICD (International Code Designator), which is a 4-digit number identifying the issuing authority, with the actual identifier assigned by that authority. This means a single field can express dozens of different identifier types including DUNS numbers, LEI codes, VAT IDs, and national business registries, all in a consistent machine-readable format. Schema.org's iso6523Code property implements this standard as an organization identifier field.

Why this matters for AEO

iso6523Code is Google's preferred format for expressing organization identifiers in structured data. Its advantage over fields like leiCode or duns is that the ICD prefix tells any consuming system exactly which registry issued the identifier and how to validate it. An AI answer engine reading an ISO 6523-formatted code does not need to guess the identifier type: the ICD prefix is a lookup key into the ISO 6523 register of issuing authorities. This reduces interpretation ambiguity and makes entity disambiguation more reliable across multilingual and multi-jurisdictional knowledge graphs.

What the specs say

Schema.org:iso6523Code expects a Text value. An organization identifier as defined in ISO 6523(-1). The identifier should be in the XXXX:YYYYYY:ZZZ or XXXX:YYYYYY format. [Source: https://schema.org/iso6523Code]

Google: Recommended. "The ISO 6523 identifier of your organization, if applicable." Google's documentation also positions iso6523Code as the preferred way to express identifiers that can also be expressed through leiCode, duns, or vatID. [Source: https://developers.google.com/search/docs/appearance/structured-data/organization]

How to find your value

To construct an ISO 6523 code, you need two things:

1. Your identifier value (e.g., your DUNS number, your LEI, your VAT ID)
2. The correct ICD prefix for the issuing authority

Common ICD codes:

• 0060 — DUNS (Dun & Bradstreet)
• 0199 — LEI (Global LEI Foundation, ISO 17442)
• 0096 — MARLIN (GS1 Global Location Numbers)
• 0208 — Belgian enterprise number (KBO/BCE)
• 0190 — National Business Registry (Denmark CVR)

The complete list of registered ICD codes is maintained by Kantara Initiative (previously by EDIRA) and is available as a downloadable register from ISO.

For most organizations, the practical path is: identify which business ID you already have (DUNS, LEI, national number), look up its ICD from the register, and format the code as ICD:IDENTIFIER.

Format and code

The format is XXXX:YYYYYY where XXXX is the 4-digit ICD and YYYYYY is the organization-specific identifier value. An optional third component :ZZZ may follow for sub-entity identification.

Expressing an LEI via ISO 6523 format (ICD 0199):

{
  "@context": "https://schema.org",
  "@type": "Organization",
  "name": "Apple Inc.",
  "iso6523Code": "0199:HWUPKR0MPOU8FGXBT394"
}

Expressing a DUNS number via ISO 6523 format (ICD 0060):

{
  "@context": "https://schema.org",
  "@type": "Organization",
  "name": "Microsoft Corporation",
  "iso6523Code": "0060:081166849"
}

Invalid formats:

{
  "iso6523Code": "HWUPKR0MPOU8FGXBT394"
}

That is missing the ICD prefix, making it uninterpretable as an ISO 6523 code.

{
  "iso6523Code": "LEI:HWUPKR0MPOU8FGXBT394"
}

Use the numeric ICD code (0199), not a text abbreviation (LEI).

Webflow implementation

Static pages

Add to your homepage or About page via Page Settings > Custom Code > Head Code:

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Organization",
  "name": "Your Company",
  "iso6523Code": "0199:YOUR20CHARLEICODE00"
}
</script>

CMS template pages

iso6523Code is an organization-level field. It belongs in a site-wide organization schema, not a per-page CMS binding.

In Schema HQ

iso6523Code is emitted in the Organization schema editor under the Disambiguation section. Enter the full formatted code including the ICD prefix and colon separator. Schema HQ publishes it as part of the organization JSON-LD block on every enabled page.

Real examples

Apple Inc. expressed using its LEI (ICD 0199):

{
  "@context": "https://schema.org",
  "@type": "Organization",
  "name": "Apple Inc.",
  "url": "https://www.apple.com",
  "iso6523Code": "0199:HWUPKR0MPOU8FGXBT394"
}

A Belgian company using its KBO/BCE enterprise number (ICD 0208):

{
  "@context": "https://schema.org",
  "@type": "Organization",
  "name": "Bekaert NV",
  "iso6523Code": "0208:0405432225"
}

Related fields

• leiCode
• duns
• vatID
• taxID
• globalLocationNumber

FAQ

Can iso6523Code replace leiCode and duns?

Yes. iso6523Code can express the same underlying identifier that leiCode or duns would express, but in a more structured format. Google's documentation explicitly positions it as the preferred alternative. For a new implementation, using iso6523Code with the correct ICD is the cleaner approach. For backward compatibility, including both the specific field (leiCode) and the ISO 6523 form is also valid.

Where is the full list of ICD codes?

The official ICD register is maintained under ISO 6523-2. A searchable version has historically been available through industry bodies. A practical reference list for common ICD codes used in European e-procurement is published by the European Commission's Peppol network.

Is the colon part of the format?

Yes. The colon (:) is the required separator between the ICD and the identifier value. A value without the colon is not a valid ISO 6523 code.