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Agent402 VAT Number Format Validator
x402
Agent402 VAT Number Format Validator is a paid API for AI agents from agent402.co.uk, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).
Validates VAT number format against official rules for EU27, GB, XI, and EL country codes without performing live VIES database checks
Price / call$0.001
Success—
StatusUnknown
How this service works
Don't burn tokens on deterministic work. Go/no-go jobs first: payout preflight, text firewall (PII/secrets), budget check — then rails, calendars, finmath. x402 USDC on Base. UK + global. agent402.co.uk — not agent402.tools. $0.001–$0.002 USDC on Base. No API keys.
Output
Returns a JSON object containing the resolved country code (e.g. 'DE'), a boolean 'valid_format' indicating whether the VAT number matches the country's structural rules, and a boolean 'known_rule' indicating whether Agent402 has a format rule for that country. Does not perform live VIES registry lookups.
Example use cases
Pre-invoice VAT format gate
“I'm about to generate an invoice for a French customer with VAT number FR83404833048 — can you verify the format is correct before I proceed?”
UK post-Brexit VAT validation
“Check if GB123456789 is a correctly formatted UK VAT number — I need to confirm the structure before processing this B2B order.”
Northern Ireland XI prefix check
“Is XI123456789 a valid VAT number format for Northern Ireland? I want to make sure it follows the right rules before I add it to our supplier records.”
Technical details
Endpoint
POSThttps://agent402.co.uk/v1/validate/vat-formatWhen to prefer
Use this endpoint as a lightweight pre-flight check before any tax, invoice, or B2B payment workflow where you need to confirm a VAT number is structurally plausible without triggering a live VIES call. Prefer it when you want fast, cheap, offline structural validation across EU27, GB, XI, and EL country codes. It is not a substitute for live VIES validation when legal compliance requires confirmed registration status.
Side effects
- Unrecognized country prefix returns known_rule: false with valid_format: false
- Malformed input with no prefix and no country parameter may return an error or ambiguous result
- Country code mismatch between prefix and optional country parameter may produce inconsistent results
- EL vs GR ambiguity for Greece may cause issues if not handled correctly by caller
- No live registry check means a structurally valid number may still be unregistered
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| vat | string | VAT with country prefix |
| country | string | Optional ISO if body has no prefix |
Output
Schema · Response
{
"type": "json",
"example": {
"country": "DE",
"known_rule": true,
"valid_format": true
}
}Tags
x402
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