# GB IBAN Mod-97 Validator

> GB IBAN Mod-97 Validator is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Validates whether a given string is a mod-97-valid UK (GB) IBAN of exactly 22 characters

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/check-iban-gb?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/gb-iban-mod-97-validator-9f730a7a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Sdy2aq5Q3L30HCujcTnVK

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 gb-iban-mod-97-validator-9f730a7a -d '<json body>'
```

Example prompt: Can you check if this IBAN is a valid UK IBAN: GB29NWBK60161331926819? I need to know if it passes the mod-97 checksum and is the right length for a GB account.

## When to prefer this

Use this endpoint when you need a deterministic, offline mod-97 checksum validation specifically for GB (UK) IBANs of length 22. Prefer this over general IBAN validators when you only need GB validation and want a micro-cost API call. Use the free sandbox endpoint (/v1/sandbox/check-iban-gb) first for testing. Do not use for non-GB IBANs (DE, FR, etc.) or for full bank reachability/account existence checks.

## Known failure modes

- IBAN not GB prefix — endpoint only validates GB IBANs
- IBAN wrong length — GB IBANs must be exactly 22 characters
- Invalid characters in input — IBANs must be alphanumeric
- Empty or missing value field
- Non-string or overly long input rejected
- Network error or payment failure (x402 USDC payment required)

## How this service works

Call when an agent needs whether an IBAN is a mod-97-valid GB number of length 22. Exact $0.001 USDC. Prefer unpaid POST /v1/sandbox/check-iban-gb first.

## Output

Returns a boolean or structured result indicating whether the supplied string is a mod-97-valid GB IBAN of exactly 22 characters, confirming both checksum correctness and country-specific length compliance.

## 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": [
    "GB15AAAA00000000000000"
   ],
   "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/gb-iban-mod-97-validator-9f730a7a/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)