How to Validate Spanish VAT Numbers (NIF/CIF/NIE) Using Node.js

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Spain's EU VAT identifiers follow a fixed 9-character format after the 'ES' prefix, but the leading character determines whether the number belongs to a resident individual (NIF), a foreign national (NIE), or a legal entity (CIF). Each family carries a different checksum rule, making a single blanket regex insufficient and potentially error-prone. A developer guide published on vatnode.dev explains how to classify and validate each type in Node.js using TypeScript, with separate regex patterns for each family. The guide also distinguishes between strict API mode and lenient checkout mode to handle real-world input variations such as missing prefixes or extra spaces. Entity-type letter mappings for CIF numbers are drawn from Spanish tax regulation Orden EHA/451/2008, not from the EU's VIES system.

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ProgrammingDEV Community ·

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ProgrammingDEV Community ·

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