# code402 RFC / Business Identifier Validator

> code402 RFC / Business Identifier Validator is a paid API for AI agents from hcrb.in, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-12).

Performs offline, deterministic checksum and format validation of business and financial identifiers (IBAN, LEI, VAT, ABA, EIN, IFSC, SWIFT/BIC, ISBN, SEDOL, etc.), paid per call via x402 USDC micropayments.

## Facts

- Endpoint: POST https://hcrb.in/v1/tools/rfc-check/call?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/code402-rfc-business-identifier-validator-b4b33ffb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_McZskPM1HXgG8lqlrU_4X

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 code402-rfc-business-identifier-validator-b4b33ffb -d '<json body>'
```

Example prompt: Can you check whether this IBAN is valid: GB29 NWBK 6016 1331 9268 19? I need to know if the checksum passes and what country it belongs to.

## When to prefer this

Choose this endpoint when you need fast, offline, deterministic validation of structured financial or business identifiers without relying on ML models or live registry lookups. It is ideal for KYB/KYC pipelines, payment pre-validation, and compliance workflows where you need cryptographically verifiable results with signed receipts. Prefer it over live registry APIs when latency, cost, or privacy constraints make external lookups undesirable, and when checksum-level confidence is sufficient.

## Known failure modes

- Unrecognized identifier type — returns valid: false with reason explaining the format was not matched
- Malformed input string — returns valid: false with reason describing the structural failure
- Payment failure via x402 — call rejected before processing if USDC micropayment not settled
- Rate limit exceeded (more than 3 free calls/day without payment) — HTTP 402 response requiring payment
- Network/service downtime — HTTP 5xx error

## How this service works

Offline deterministic checks (no ML, no scraping) for business identifiers and rental due-diligence, paid per call via x402 (gasless EIP-3009 USDC on Base). Checksum-verifiable (IBAN, LEI, VAT, ABA, ISBN, SEDOL…) vs format-only (EIN, IFSC, SWIFT/BIC…) — every response returns a scope field. Non-custodial, signed receipts. First 3 calls/day free.

## Output

Returns a JSON object with: `valid` (boolean indicating pass/fail), `reason` (human-readable explanation such as 'checksum valid' or 'invalid format'), `scope` (whether the check was checksum-verifiable or format-only), `normalized` (canonically formatted identifier), `country` (if applicable), and `tool` (identifier type detected).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "rfc"
   ],
   "properties": {
    "rfc": {
     "type": "string",
     "description": "12 or 13 character Mexican RFC (e.g. BBA830831LJ2)."
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "schema": {
  "type": "object",
  "required": [
   "valid",
   "reason"
  ],
  "properties": {
   "tool": {
    "type": "string"
   },
   "scope": {
    "type": "string"
   },
   "valid": {
    "type": "boolean"
   },
   "reason": {
    "type": "string"
   },
   "country": {
    "type": "string"
   },
   "normalized": {
    "type": "string"
   }
  }
 },
 "example": {
  "valid": true,
  "reason": "checksum valid"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/code402-rfc-business-identifier-validator-b4b33ffb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from hcrb.in](https://www.zero.xyz/host/hcrb.in/llms.txt)