# code402 ABN Validator

> code402 ABN Validator is a paid API for AI agents from hcrb.in, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-11).

Validates an Australian Business Number (ABN) using offline deterministic checksum verification, returning validity, reason, and normalized form.

## Facts

- Endpoint: POST https://hcrb.in/v1/tools/abn-check/call?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/code402-abn-validator-be807c05
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ytDwkazG8KPHD9fsf2Yb0

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-abn-validator-be807c05 -d '<json body>'
```

Example prompt: Can you check whether ABN 51 824 753 556 is valid and correctly formatted?

## When to prefer this

Choose this endpoint when you need fast, offline, deterministic ABN validation with no dependency on external registries or ML models — ideal for real-time onboarding flows, invoice processing, or compliance checks where you need a verifiable, signed receipt of the validation result. Prefer it over web-scraping or ASIC registry lookups when you only need format/checksum correctness and want per-call micropayment billing without a subscription.

## Known failure modes

- Invalid or malformed ABN input returns valid:false with a descriptive reason
- Non-ABN identifier passed to the endpoint may return an error or format rejection
- After 3 free daily calls, payment via x402/USDC on Base is required — missing payment header results in 402 response
- Network or server errors may return non-JSON HTTP error responses

## 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

A JSON object with: `valid` (boolean indicating checksum pass/fail), `reason` (human-readable explanation such as 'checksum valid' or specific failure reason), `scope` (indicating whether validation is checksum-level or format-only), `normalized` (canonically formatted ABN string), `country` (AU), and `tool` (identifier for the specific check performed).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "abn"
   ],
   "properties": {
    "abn": {
     "type": "string",
     "description": "11-digit Australian Business Number; spaces allowed."
    }
   }
  }
 }
}
```

## 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-abn-validator-be807c05/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)