EIN for test fixtures
Automated tests that touch an EIN field cannot reuse a real company's number, so this page shows how to generate a synthetic EIN with a valid IRS prefix, the XX-XXXXXXX shape and a reproducible seed, ready for a fixture, a homologation dataset or a masked-field contract test.
20 sits among the 17 prefixes of the 'Internet' campus, the group most fixtures reach for because it represents an EIN issued through the IRS online application, the standard onboarding path.
01 belongs to Brookhaven, the campus with the most prefixes in the table (24 of the 83), handy for testing the less common generation path when a test needs to deliberately avoid prefix 20.
SBA is the narrowest campus in the table: only prefix 31 belongs to it, so any test EIN with that prefix always points to the same campus, with no variation possible.
Not like CPF/CNPJ. Basic validation uses length and IRS-valid prefixes.
Pass the same `DigitSource` function as the seed into `generateEin`; since prefix and serial selection depend only on it, the same seed always reproduces the same XX-XXXXXXX value, so you never have to hardcode the final number in the test.
Yes: the generator exposes `raw` (9 digits, no separator) and `formatted` (dash after the first 2 digits); a masked field can take `raw` and format it itself, and a contract test should compare both against the same normalized value.
Yes, `generateEinBatch(count, source, campusId)` returns the already-validated array; restricting by `campusId` helps isolate one specific path, but a narrow campus, like SBA with only 1 prefix, repeats that prefix constantly across a large batch.
The same underlying value: the generated document's `raw` field already comes without a dash, ready to paste straight into a digits-only input or to build the payload for a test API call.
Generation happens locally in the browser. Analytics receives only action, status, type and format, never the generated EIN.