Validates an International Securities Identification Number (ISIN) as defined by ISO 6166. An ISIN is a 12-character alphanumeric code that uniquely identifies a financial instrument worldwide: 2-letter ISO country code, 9-character NSIN (National Securities Identifying Number), and 1 check digit verified using a Luhn-based algorithm.

When the ISIN is structurally valid, the endpoint looks up instrument details from two sources simultaneously. ESMA FIRDS (the EU regulatory reference database under MiFID II, synchronised daily) provides the richest data for European instruments. OpenFIGI (Bloomberg) extends coverage to global instruments such as US equities. Both sources are queried in parallel and their fields are merged into a single response. The dataSource field indicates which source(s) returned data: firds, openfigi, or firds+openfigi when both found the instrument. Fields from an unavailable or non-matching source are returned as null. OpenFIGI results are cached for 24 hours. Whitespace in the input is stripped automatically.

XT-ISINs (prefix XT) identify digital tokens registered with the Digital Token Identifier Foundation (DTIF) under ISO 24165. They share the same 12-character structure and Luhn check digit as regular ISINs. No enrichment data from FIRDS or OpenFIGI is available for digital tokens, so XT-ISINs always return found: false. Note: the NSIN of an XT-ISIN is assigned independently by the numbering authority and is not the same as the token's DTI (ISO 24165 identifier).

Guides: Node.js · Python

Query Parameters

Example Request

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.isvalid.dev/v0/isin?value=US0378331005"

Response Fields

Example Response — found in both sources

{
  "valid": true,
  "countryCode": "PL",
  "countryName": "Poland",
  "nsin": "000PKN0RH1",
  "cusip": null,
  "checkDigit": "6",
  "found": true,
  "dataSource": "firds+openfigi",
  "name": "PKN ORLEN SA",
  "fisn": "PKN ORLEN SA/SHS",
  "cfiCode": "ESVUFR",
  "currency": "PLN",
  "tradingVenue": "XWAR",
  "issuerLei": "259400VMBIZKDL26YB25",
  "maturityDate": null,
  "status": "ACTV",
  "ticker": "PKN",
  "exchCode": "WSE",
  "securityType": "Common Stock",
  "marketSector": "Equity",
  "figi": "BBG000BW0VH6",
  "compositeFIGI": "BBG000BW0VH6"
}

Example Response — found via FIRDS only (EU instrument not in OpenFIGI)

{
  "valid": true,
  "countryCode": "PL",
  "countryName": "Poland",
  "nsin": "000PKN0RH1",
  "cusip": null,
  "checkDigit": "6",
  "found": true,
  "dataSource": "firds",
  "name": "PKN ORLEN SA",
  "fisn": "PKN ORLEN SA/SHS",
  "cfiCode": "ESVUFR",
  "currency": "PLN",
  "tradingVenue": "XWAR",
  "issuerLei": "259400VMBIZKDL26YB25",
  "maturityDate": null,
  "status": "ACTV",
  "ticker": null,
  "exchCode": null,
  "securityType": null,
  "marketSector": null,
  "figi": null,
  "compositeFIGI": null
}

Example Response — found via OpenFIGI only (non-EU instrument)

{
  "valid": true,
  "countryCode": "US",
  "countryName": "United States",
  "nsin": "037833100",
  "cusip": "037833100",
  "checkDigit": "5",
  "found": true,
  "dataSource": "openfigi",
  "name": "APPLE INC",
  "fisn": null,
  "cfiCode": null,
  "currency": null,
  "tradingVenue": null,
  "issuerLei": null,
  "maturityDate": null,
  "status": null,
  "ticker": "AAPL",
  "exchCode": "UN",
  "securityType": "Common Stock",
  "marketSector": "Equity",
  "figi": "BBG000B9XRY4",
  "compositeFIGI": "BBG000B9XRY4"
}

Example Response — terminated instrument

{
  "valid": true,
  "countryCode": "DE",
  "countryName": "Germany",
  "nsin": "000A0MR4U3",
  "cusip": null,
  "checkDigit": "4",
  "found": true,
  "dataSource": "firds",
  "name": "EXAMPLE BOND 2020",
  "fisn": "EXAMPLE BOND/FLT 14-20",
  "cfiCode": "DBFNFR",
  "currency": "EUR",
  "tradingVenue": "XFRA",
  "issuerLei": "5299009XBDRSN8D5E918",
  "maturityDate": "2020-12-31",
  "status": "TERM",
  "ticker": null,
  "exchCode": null,
  "securityType": null,
  "marketSector": null,
  "figi": null,
  "compositeFIGI": null
}

Example Response — not found

{
  "valid": true,
  "countryCode": "US",
  "countryName": "United States",
  "nsin": "037833100",
  "cusip": "037833100",
  "checkDigit": "5",
  "found": false
}

Example Response — data sources unavailable

{
  "valid": true,
  "countryCode": "US",
  "countryName": "United States",
  "nsin": "037833100",
  "cusip": "037833100",
  "checkDigit": "5",
  "found": null
}

Example Response — XT-ISIN (digital token, Bitcoin)

{
  "valid": true,
  "countryCode": "XT",
  "countryName": "Digital Tokens (ISO 24165)",
  "nsin": "V15WLZJMF",
  "cusip": null,
  "checkDigit": "0",
  "found": false
}

Example Response — invalid

{
  "valid": false
}