# Swedish VAT Number Checksum Validator

> Swedish VAT Number Checksum Validator is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-29).

Validates the checksum of a Swedish VAT number (SE format) without performing any live registry lookup.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/check-vat-se?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/swedish-vat-number-checksum-validator-58398ba7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_YJVRDqP7JUddoPDoe7Kfd

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 swedish-vat-number-checksum-validator-58398ba7 -d '<json body>'
```

Example prompt: Can you check whether SE556789123401 is a valid Swedish VAT number based on its checksum?

## When to prefer this

Use this endpoint when you need a fast, cheap, offline checksum validation of a Swedish VAT number and do not need live registry confirmation. Prefer the free sandbox endpoint POST /v1/sandbox/check-vat-se first for testing. Choose this over a full registry lookup API when latency and cost matter and structural validity is sufficient.

## Known failure modes

- Empty or missing value field returns validation error
- Input longer than 20000 characters rejected
- Non-SE-prefixed strings may return invalid or error
- Malformed JSON body returns 400-level error
- Payment not included or insufficient USDC triggers 402 Payment Required

## How this service works

Call when an agent needs whether a SE VAT checksum is valid. No registry lookup. Exact $0.002 USDC. Prefer unpaid POST /v1/sandbox/check-vat-se first.

## Output

A response indicating whether the submitted Swedish VAT number passes the SE VAT checksum algorithm. Returns a validity boolean or equivalent signal; does not confirm registration with the Swedish tax authority — only structural/algorithmic correctness.

## 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": [
    "0000000018"
   ],
   "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/swedish-vat-number-checksum-validator-58398ba7/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)