# Toll402 Austrian VAT Number Validator

> Toll402 Austrian VAT Number Validator is a paid API for AI agents from toll402.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Validates an Austrian UID/VAT number (format ATU + 8 digits) offline using format normalization and weighted modulo-10 check digit verification

## Facts

- Endpoint: POST https://toll402.dev/v1/t/vat_at_validate
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/toll402-austrian-vat-number-validator-edb22104
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_GSRSL_HGomeuExxBoC2nF

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability toll402-austrian-vat-number-validator-edb22104 -d '<json body>'
```

Example prompt: Can you check whether ATU12345675 is a valid Austrian VAT number — verify the format and the check digit?

## When to prefer this

Use this endpoint when you need fast, offline, zero-latency validation of Austrian UID/VAT numbers without making external calls to Austrian tax authority APIs. Ideal for pre-submission checks, form validation, onboarding flows, and invoice processing where you only need structural and check-digit correctness rather than live government database confirmation.

## Known failure modes

- Missing or malformed uid field returns validation error
- UID with wrong prefix (not ATU) fails format check
- UID with wrong digit count fails structure check
- UID with correct format but invalid check digit returns invalid result
- Empty string input returns error

## How this service works

Offline validator for an Austrian UID (VAT) number: format ATU followed by 8 digits. Normalizes input, checks structure and verifies the weighted modulo-10 check digit algorithm (weights 1,2,1,2,1,2,1 on the first 7 digits, digit-sum reduction, check = (10-(sum+4)%10)%10).

## Output

Returns whether the provided UID string is a valid Austrian VAT number, including whether it passes format normalization (ATU prefix + 8 digits) and the weighted modulo-10 check digit algorithm (weights 1,2,1,2,1,2,1 on first 7 digits, check digit verified as (10-(sum+4)%10)%10).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "uid"
     ],
     "properties": {
      "uid": {
       "type": "string",
       "description": "Austrian UID/VAT number, e.g. ATU12345675"
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/toll402-austrian-vat-number-validator-edb22104/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from toll402.dev](https://www.zero.xyz/host/toll402.dev/llms.txt)