WKN

GET/v0/wkn

Validates a WKN (Wertpapierkennnummer, also WPKN or WPK) — the 6-character alphanumeric identifier assigned by WM Datenservice (formerly Wertpapier-Mitteilungen) to German securities. A WKN consists of exactly 6 uppercase alphanumeric characters ([A-Z0-9]). Unlike ISIN or CUSIP, the WKN has no check digit — validation is purely format-based. Whitespace and lowercase input are handled automatically.

WKNs are embedded in German ISINs: the NSIN of a DE… ISIN is the WKN zero-padded to 9 characters. For example, ISIN DE0005140008 contains WKN 514000 (NSIN 000514000).

When the WKN is structurally valid, the endpoint queries OpenFIGI (Bloomberg) using idType: ID_WERTPAPIER to retrieve instrument details. Results are cached for 24 hours.

Guides: Node.js · Python

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Query Parameters

Parameter	Type	Required	Description
value	string	Yes	The 6-character WKN to validate (e.g. `514000`)

Example Request

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/wkn?value=514000"

Response Fields

Field	Type	Description
valid	boolean	Whether the value is a valid 6-character alphanumeric WKN
wkn	string	The normalised (uppercased, whitespace-stripped) WKN
found	boolean \| null	Whether the instrument was found in OpenFIGI. `true` — found, instrument details included; `false` — structurally valid WKN but not found in OpenFIGI; `null` — OpenFIGI unavailable, structural validation result only
dataSource	string	Always `openfigi` when present. Present only when `found` is `true`
isin	string \| null	ISIN associated with this WKN as returned by OpenFIGI (e.g. `DE0005140008`). Present when `found` is `true`; `null` if not returned
name	string \| null	Full instrument name (e.g. `Deutsche Bank AG`). Present when `found` is `true`
ticker	string \| null	Exchange ticker symbol. From OpenFIGI; `null` if not provided
exchCode	string \| null	Bloomberg exchange code (e.g. `GY` for XETRA). From OpenFIGI; `null` if not provided
securityType	string \| null	Security type from OpenFIGI (e.g. `Common Stock`). From OpenFIGI; `null` if not provided
marketSector	string \| null	Market sector from OpenFIGI (e.g. `Equity`). From OpenFIGI; `null` if not provided
figi	string \| null	Financial Instrument Global Identifier. From OpenFIGI; `null` if not provided
compositeFIGI	string \| null	Composite FIGI representing the instrument across all exchanges. From OpenFIGI; `null` if not provided

Example Response — found

{
  "valid": true,
  "wkn": "514000",
  "found": true,
  "dataSource": "openfigi",
  "isin": "DE0005140008",
  "name": "Deutsche Bank AG",
  "ticker": "DBK",
  "exchCode": "GY",
  "securityType": "Common Stock",
  "marketSector": "Equity",
  "figi": "BBG000BC5588",
  "compositeFIGI": "BBG000BC5588"
}

Example Response — not found

{
  "valid": true,
  "wkn": "514000",
  "found": false
}

Example Response — invalid

{
  "valid": false
}