VAT Number Format Check

Check European VAT number formats against country patterns. Returns the country and format result without checking registration or check digits.

Pay by wallet (x402) vat-format-validate

Example

Input

{
  "vat_number": "SE556703748501"
}

Answer

{
  "note": "Format is valid. Use vat-validate for full VIES verification.",
  "valid": true,
  "vat_number": "SE556703748501",
  "country_code": "SE",
  "country_name": "Sweden",
  "format_valid": true,
  "expected_format": "SE123456789012"
}

Inputs

Field	Type	Required	What it is
`vat_number`	string	Yes	VAT number including country prefix (e.g. SE556703748501)

Output fields

How reliably each field appears in a successful answer.

Field	Type	Appears
`valid`	boolean	Always (present in every successful answer)
`vat_number`	string	Always (present in every successful answer)
`country_code`	string	Always (present in every successful answer)
`country_name`	string	Always (present in every successful answer)
`format_valid`	boolean	Always (present in every successful answer)

How to call it

The same tool through each route. MCP clients reach it through Strale’s server at https://api.strale.io/mcp; the call below is what the agent sends.

# Needs an API key. max_price_cents caps what this call may cost.
curl -X POST https://api.strale.io/v1/do \
  -H "Authorization: Bearer $STRALE_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
    "capability_slug": "vat-format-validate",
    "inputs": {
      "vat_number": "SE556703748501"
    },
    "max_price_cents": 2
  }'

{
  "tool": "strale_execute",
  "arguments": {
    "slug": "vat-format-validate",
    "inputs": {
      "vat_number": "SE556703748501"
    },
    "max_price_cents": 2
  }
}

import { Strale } from "straleio";

const strale = new Strale({ apiKey: process.env.STRALE_API_KEY! });
const result = await strale.do({
  capability_slug: "vat-format-validate",
  inputs: {
    "vat_number": "SE556703748501"
  },
  max_price_cents: 2,
});

import os
from straleio import Strale, DoRequest

strale = Strale(api_key=os.environ["STRALE_API_KEY"])
result = strale.do(DoRequest(
    capability_slug="vat-format-validate",
    inputs={
        "vat_number": "SE556703748501",
    },
    max_price_cents=2,
))

# No account. The first request answers 402 with the price in USDC;
# an x402 client pays it from your wallet and repeats the request.
curl -i 'https://api.strale.io/x402/v2/vat-format-validate?vat_number=SE556703748501'

Limitations

Format checks do not confirm VAT registration
Validates the number format against country patterns only. It does not check check digits or confirm that the number is registered or active
What to do instead: Use vat-validate for VIES database confirmation after format validation passes