# Delx IBAN Checksum Validator

> Delx IBAN Checksum Validator is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Validates an IBAN string by verifying its checksum, returning a boolean validity result.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/iban-checksum
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-iban-checksum-validator-2584e239
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nMKv0ipvVN7ZTKDrXcAPo

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 delx-iban-checksum-validator-2584e239 -d '<json body>'
```

Example prompt: Can you check whether this IBAN is valid: GB29NWBK60161331926819?

## When to prefer this

Use this endpoint when you need a lightweight, low-cost (sub-cent) IBAN checksum check without a full banking API integration — ideal for pre-validating user-supplied IBANs before initiating payments, cleaning financial datasets, or gating form submissions. Prefer this over full payment processors when you only need structural IBAN validation, not account existence or reachability checks.

## Known failure modes

- Missing or empty 'iban' field returns a validation error
- Malformed or non-IBAN string may return valid:false rather than an error
- Network timeout on rare occasions causing request failure
- Invalid JSON body in request returns a 400-level error

## How this service works

Validate IBAN checksum (mod 97) offline. Call when payment form validation without banking APIs. Returns valid boolean as deterministic JSON for $0.001 USDC via x402 on Base. First-party local math only—no RPC, live market feed, API keys, storage, or mediagen. Advisory only; the caller owns capital, risk, and production controls.

## Output

Returns a JSON object with a boolean 'valid' field indicating whether the IBAN checksum is correct, and a 'schema' field identifying the response format as 'delx/util-iban-checksum/v1'.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "iban": {
   "type": "string",
   "description": "IBAN string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "valid": true,
  "schema": "delx/util-iban-checksum/v1"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-iban-checksum-validator-2584e239/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)