VAT / tax-id format and check digit (AT, BE, DE, DK, FI)

$0.005 USDC per call · Business, finance and compliance · POST /api/v1/tax-id-format · Id tax-id-format

Checks the structure and check digit of up to 100 EU VAT numbers per call (Austria, Belgium, Germany, Denmark, Finland), for an agent about to put a supplier or customer VAT number on an invoice or into a record. Every other country answers unsupported rather than guessing a pattern. It never says whether the number is registered or active (that needs VIES or the national register), and a pass is not proof that the business exists.

What you get

Catches a mistyped VAT number before it reaches an invoice or a VIES lookup.

Call it

Send the JSON body below to https://agents.writerslogic.com/api/v1/tax-id-format. An unpaid request answers 402 with the price and how to pay; a request that fails with a 5xx status is not charged.

curl -i -X POST https://agents.writerslogic.com/api/v1/tax-id-format \
  -H 'content-type: application/json' \
  -d '{"items":[{"value":"ATU13585627"},{"value":"DE 136 695 978"},{"value":"FR40303265045"}]}'

Input

Field	Type	Required	Description
`items`	array<object>; max 100 items	yes

Example request body

{
  "items": [
    {
      "value": "ATU13585627"
    },
    {
      "value": "DE 136 695 978"
    },
    {
      "value": "FR40303265045"
    }
  ]
}

Result

The response is { "data": ..., "_provenance": ... }. data carries these fields; _provenance is a signed W3C Verifiable Credential with a C2PA-style manifest, checked free at POST /api/v1/verify-provenance.

Field	Type	Required	Description
`status`	string; one of "pass", "fail", "unknown", "unsupported"	no	pass: every rule held. fail: a rule was violated (see witnesses). unknown: the input lacks the evidence to decide. unsupported: outside what this engine covers. Missing evidence is never a pass.
`results`	array<object>	no
`counts`	object	no	Items per status.
`witnesses`	array<object>	no
`versions`	object	no	Every semantic dependency of this answer (engine, tables and their as-of dates, tokenizer, calendar, rounding profile).
`limits`	array<string>	no
`deterministic`	boolean	no	Always true: pure code, no model.

Pay and connect

Available through: x402 (USDC on Base), MCP. MCP clients reach it through the identifier-text-kit package.

Machine-readable

This agent as JSON (schemas, example, OpenAPI operation)
Free signed sample response
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