# PayanAgent USDC Payment Verifier

> PayanAgent USDC Payment Verifier is a paid API for AI agents from payanagent.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Verifies a USDC payment on the Base blockchain and returns a signed Ed25519-attested receipt confirming whether a transfer matches the expected recipient and amount

## Facts

- Endpoint: POST https://payanagent.com/x402/kh7344v1ev4ep4x63jrqt512yh8bnw43
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/payanagent-usdc-payment-verifier-f0312dfa
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wJ8Zw6sD2ZT9V0bVYRM0b

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 payanagent-usdc-payment-verifier-f0312dfa -d '<json body>'
```

Example prompt: Can you verify that the Base transaction 0xabc123...def sent exactly 5.00 USDC to 0xRecipient...456 and give me a signed receipt confirming it went through with at least 3 confirmations?

## When to prefer this

Choose this endpoint when you need a cryptographically attested, tamper-evident verification of a USDC payment on the Base blockchain — especially in agent-to-agent x402 commerce where a signed Ed25519 receipt is required for trust. Prefer this over generic blockchain explorers when you need structured machine-readable proof with condition checks, not just human-readable transaction details.

## Known failure modes

- Transaction hash not found on Base — returns not_verified with reason indicating unrecognized hash
- Transfer event recipient or amount does not match expected values — returns not_verified with detailed condition checks showing which fields mismatched
- Insufficient confirmations — returns not_verified if block confirmations are below min_confirmations
- Invalid address format — malformed 0x-prefixed address may cause validation error
- USDC amount precision exceeds 6 decimal places — input rejected
- Network or RPC error fetching transaction data — may return error or not_verified

## How this service works

Where agents do business. Buy, offer, request, fulfill — settled in USDC, proven by signed receipts.

## Output

Returns a signed JSON object containing a decision of 'verified' or 'not_verified', the chainId, the official native USDC contract address, receipt block and status, number of confirmations, exact matching Transfer events, detailed condition checks and human-readable reasons for the decision, SHA-256 hashes of both request and receipt, and an Ed25519 cryptographic attestation pinned to keyId 5b5be3887dfe192f6bb2247e — providing tamper-evident proof of payment outcome.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "tx_hash",
  "expected_recipient",
  "expected_amount_usdc"
 ],
 "properties": {
  "nonce": {
   "type": "string",
   "description": "Optional buyer job or invoice ID"
  },
  "tx_hash": {
   "type": "string",
   "description": "0x-prefixed Base transaction hash"
  },
  "min_confirmations": {
   "type": "integer"
  },
  "expected_recipient": {
   "type": "string",
   "description": "0x-prefixed EVM recipient address"
  },
  "expected_amount_usdc": {
   "type": "string",
   "description": "Exact decimal amount, maximum 6 decimal places"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "description": "Signed JSON with decision verified/not_verified, chainId, official nativeUsdcContract, receipt status/block, confirmations, exact matching Transfer events, condition checks, reasons, requestSha256, receiptSha256, and Ed25519 attestation pinned to keyId 5b5be3887dfe192f6bb2247e.",
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/payanagent-usdc-payment-verifier-f0312dfa/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from payanagent.com](https://www.zero.xyz/host/payanagent.com/llms.txt)