# ARAKEL x402 Transaction Proof

> ARAKEL x402 Transaction Proof is a paid API for AI agents from proof.arakelproof.space, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-13).

Verifies a Base USDC payment on-chain and returns an Ed25519-signed receipt binding that payment to specific request and response hashes, enabling machine-verifiable proof of a paid API exchange.

## Facts

- Endpoint: POST https://proof.arakelproof.space/v1/x402/receipt-verify?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/arakel-x402-transaction-proof-e0a2ad00
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tcx5l7J4FEeLTsJmt0SaA

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 arakel-x402-transaction-proof-e0a2ad00 -d '<json body>'
```

Example prompt: I need ARAKEL to verify that Base transaction 0xabc123... sent 0.003 USDC to 0xPayee456... and issue a signed receipt binding request hash 0xreq789... and response hash 0xresp321... to that payment, with at least 3 confirmations.

## When to prefer this

Choose this endpoint when you need cryptographic, machine-verifiable proof that a specific Base USDC payment funded a specific API request-response pair — particularly for autonomous agent pipelines, multi-party accountability, compliance auditing, or releasing resources contingent on verified payment. It is distinctively useful over generic blockchain explorers because it returns an Ed25519-signed binding anchoring the payment to exact content hashes, not just confirming the transaction.

## Known failure modes

- Transaction hash not found on Base chain — returns unverified decision
- Payment amount does not meet expected_amount_usdc or expected_amount_atomic — verification fails
- Expected payee does not match actual USDC recipient — binding rejected
- Insufficient confirmations below min_confirmations threshold — returns unverified
- Malformed or missing request_hash / response_hash — API error
- Transaction already used for a different binding — possible replay detection error

## How this service works

$0.001 OFAC destination-wallet preflight for autonomous agents, plus machine-verifiable official-source evidence over x402 USDC on Base.

## Output

Returns a signed JSON object conforming to schema 'arakel.x402.receipt-verify.v1', containing a payment decision (VERIFIED or not), verified boolean, the original request_hash and response_hash, an Ed25519 signature with algorithm metadata, and service_id — enabling any downstream machine to independently confirm that the named USDC payment covered the exact API exchange.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "tx": {
   "type": "string",
   "description": "Base transaction hash"
  },
  "service_id": {
   "type": "string"
  },
  "request_hash": {
   "type": "string",
   "description": "SHA-256 style 32-byte request hash for receipt binding"
  },
  "response_hash": {
   "type": "string",
   "description": "SHA-256 style 32-byte response hash for receipt binding"
  },
  "expected_payee": {
   "type": "string",
   "description": "Expected USDC recipient"
  },
  "expected_payer": {
   "type": "string",
   "description": "Optional expected USDC payer"
  },
  "min_confirmations": {
   "type": "integer",
   "maximum": 200,
   "minimum": 1
  },
  "expected_amount_usdc": {
   "type": "string",
   "description": "Expected USDC decimal amount; provide this or expected_amount_atomic"
  },
  "expected_amount_atomic": {
   "type": "string",
   "description": "Expected USDC amount in 6-decimal atomic units; provide this or expected_amount_usdc"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "schema": "arakel.x402.receipt-verify.v1",
  "payment": {
   "decision": "VERIFIED",
   "verified": true
  },
  "decision": "VERIFIED",
  "verified": true,
  "signature": {
   "alg": "Ed25519"
  },
  "request_hash": "0x…",
  "response_hash": "0x…"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/arakel-x402-transaction-proof-e0a2ad00/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from proof.arakelproof.space](https://www.zero.xyz/host/proof.arakelproof.space/llms.txt)