{"slug":"api-duoleads-com-v1-id-security-65ca1b","title":"Validate the check digit of a financial security identifier","host":"api.duoleads.com","method":"GET","resource":"https://api.duoleads.com/v1/id/security","category":"code","description":"Validate the check digit of a financial security identifier: ISIN (ISO 6166), CUSIP, SEDOL and FIGI. Returns the verdict, the computed correct check character, and for an ISIN the issuing country prefix and the embedded NSIN. Also builds an ISIN from a country code plus a 9-character NSIN. Format an","price_listed":0.05,"price_asked":0.05,"state":"answering","state_label":"Answering","checks_7d":1,"answered_7d":1,"latency_ms_median":21,"reported_calls_30d":1,"reported_payers_30d":1,"networks":["eip155:8453"],"badge":"unverified","paid_checks_7d":0,"paid_ok_7d":0,"example_input":{"method":"GET","queryParams":{"value":"US0378331005"},"type":"http"},"output_schema":{"$schema":"https://json-schema.org/draft/2020-12/schema","properties":{"input":{"additionalProperties":false,"properties":{"method":{"enum":["GET"],"type":"string"},"queryParams":{"properties":{"country":{"description":"ISO 3166-1 alpha-2 code or XS. Required when op=build-isin.","maxLength":16,"type":"string"},"nsin":{"description":"Exactly 9 alphanumeric characters. Required when op=build-isin.","maxLength":64,"type":"string"},"op":{"default":"validate","description":"validate (default) or build-isin.","enum":["validate","build-isin"],"maxLength":64,"type":"string"},"value":{"description":"ISIN, CUSIP, SEDOL or FIGI to validate. Required when op=validate.","maxLength":24,"type":"string"}},"required":[],"type":"object"},"type":{"const":"http","type":"string"}},"required":["type","method"],"type":"object"},"output":{"properties":{"example":{"properties":{"data":{"type":"object"},"meta":{"properties":{"computed_at":{"type":"string"},"deterministic":{"type":"boolean"},"disclaimer":{"type":"string"},"price_usd":{"type":"string"},"request_id":{"type":"string"},"sources":{"type":"array"}},"required":["request_id","computed_at","price_usd","deterministic","disclaimer"],"type":"object"},"ok":{"const":true,"type":"boolean"},"route":{"type":"string"},"version":{"type":"string"}},"required":["ok","route","version","data","meta"],"type":"object"},"type":{"type":"string"}},"required":["type"],"type":"object"}},"required":["input"],"type":"object"},"history":[{"day":"2026-09-29","reachable":true,"status":402,"valid_402":true,"asked_usdc":0.05,"price_match":true,"latency_ms":21,"error":null}],"description_full":"Validate the check digit of a financial security identifier: ISIN (ISO 6166), CUSIP, SEDOL and FIGI. Returns the verdict, the computed correct check character, and for an ISIN the issuing country prefix and the embedded NSIN. Also builds an ISIN from a country code plus a 9-character NSIN. Format and checksum only, no security master lookup.","last_updated":"2026-09-28T23:37:24.338Z","schemes":["exact"]}