Generator · US data

US Employer Identification Number

Endpoint GET /v1/us/ein

What it covers

Returns a synthetic US Employer Identification Number — the federal taxpayer number the IRS issues to businesses, formatted `NN-NNNNNNN`. The EIN carries **no checksum**: its only structural rule is that the two-digit prefix must be one the IRS actually issues, so `invalid=true` violates that prefix (or the nine-digit mask) instead. Since 2001 the prefix identifies the assigning campus or the online SS-4 programme, **not** the business’s location. Pin it with `prefix`; an unissued prefix is rejected with a 400.

Parameters

ParameterTypeDescription
countinteger1–10000Number of records to return, 1–10000. Omitted returns a single record; set it for a batch. Costs 1 token plus a tenth per record.
edgebooleanRestrict output to valid edge cases from the rare corners of the domain.
extremebooleanReturn a correct value wrapped in a hostile encoding (untrimmed whitespace, invisible/zero-width characters, BOM, or bidi/combining marks). Homoglyphs are excluded so the value stays machine-parseable; it still validates after normalisation.
format"plain" | "with-hyphen"Rendering: `with-hyphen` (default, `12-3456789`) or `plain` (9 bare digits).
invalidbooleanReturn a deliberately invalid value that fails validation, for testing rejection paths.
prefixstringpattern ^\d{2}$Pin the two-digit IRS campus prefix, e.g. `20` (Internet) or `04` (Brookhaven).
seedintegerInteger seed for reproducible output: the same seed always yields the same record.

Response fields

FieldTypeDescription
valuestringThe EIN rendered per `format` (hyphenated by default).
digitsstringThe canonical nine digits, unformatted.
prefixstringThe two-digit IRS campus prefix.
serialNumberstringThe seven-digit serial following the prefix.
campusstringThe IRS campus or programme issuing this prefix, e.g. `Ogden`, `Internet`.

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The same kind of identifier elsewhere

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