Lookup

Look up a number, and ask whether it was valid on a given date.

Qualified invoice issuers

curl https://api.daichodo.com/v1/invoice-issuers/T8000000000001 \
  -H "Authorization: Bearer dc_live_..."

An unregistered number returns 404. A malformed one returns 400. These are deliberately different: "well-formed but not registered" and "not a number at all" mean different things to the caller.

Corporate numbers

curl https://api.daichodo.com/v1/corporations/8000000000001 \
  -H "Authorization: Bearer dc_live_..."

Validity on a given date

curl "https://api.daichodo.com/v1/invoice-issuers/T8000000000001/validity?on=2024-06-30" \
  -H "Authorization: Bearer dc_live_..."

{
  "registration_number": "T8000000000001",
  "on": "2024-06-30",
  "valid": true,
  "reason": "valid",
  "registered_on": "2023-10-01",
  "ended_on": null
}

reason says why, and takes one of three values — branch on it rather than on valid alone if you need to tell the cases apart:

registered_on and ended_on are the window itself. ended_on is null for a registration that is still current.

This is the one that matters in practice. Whether input tax credit applies turns on the registration's status on the invoice date, which current state cannot tell you.

The answer is derived from our own accumulated change log, so it does not depend on the source being reachable. Available on paid plans.

Sole traders

For a corporation the registration number is the corporate number with a T in front. A sole trader's 13 digits are not a corporate number and will not be found in the corporate register — but they come from the same numbering scheme, so the check digit applies to them just the same. Measured over the whole register: 5,421,496 numbers, zero exceptions.

That means the number alone cannot tell you which kind of entity you are holding. This endpoint can: corporate_number is null for a sole trader, and kind says which it is.

Sole traders are in the register and retain their date fields, so validity-on-a-date works for them exactly as it does for corporations. Some registrations publish no name, in which case name is null — that is the absence of published data, not an incomplete record to be filtered out.

Attribution

Daichodo is not affiliated with, or endorsed by, the National Tax Agency. Source attribution appears in the footer of every page.