# Croatian VAT Number Checksum Validator

> Croatian VAT Number Checksum Validator is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-02).

Validates whether a Croatian (HR) VAT number passes the checksum algorithm, without performing a live registry lookup.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/check-vat-hr?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/croatian-vat-number-checksum-validator-8884df75
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6ESYQlGx_ZvdHoul9sK9A

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 croatian-vat-number-checksum-validator-8884df75 -d '<json body>'
```

Example prompt: Can you check if the Croatian VAT number HR12345678901 has a valid checksum — I just need to know if the number itself is structurally correct, no registry lookup needed.

## When to prefer this

Use this endpoint when you need a fast, cheap, offline checksum-only validation of a Croatian (HR) VAT number and do not need to confirm the number is actually registered with the Croatian tax authority. Prefer the free sandbox endpoint /v1/sandbox/check-vat-hr for testing before paying.

## Known failure modes

- Empty or missing value field returns an error
- Non-string or overly long input may be rejected
- Input that is not a recognizable HR VAT format may return invalid without detailed error
- Payment not included results in HTTP 402 response

## How this service works

Call when an agent needs whether a HR VAT checksum is valid. No registry lookup. Exact $0.004 USDC. Prefer unpaid POST /v1/sandbox/check-vat-hr first.

## Output

Returns a boolean or structured result indicating whether the provided Croatian VAT number passes the HR VAT checksum algorithm. No external registry is contacted; only mathematical validity is confirmed.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "description": "JSON value for schema-check SKUs. Omit it on string checks such as email or IBAN."
  },
  "value": {
   "type": "string",
   "examples": [
    "00000000029"
   ],
   "maxLength": 20000,
   "minLength": 1,
   "description": "Value to check. The route description names the format: email, phone, IBAN, postal code, VAT, national id, or similar."
  },
  "schema": {
   "description": "JSON Schema document for schema-check SKUs. Omit it on string checks."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/croatian-vat-number-checksum-validator-8884df75/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)