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Proofwork Base USDC Receipt Verifier
x402
Proofwork Base USDC Receipt Verifier is a paid API for AI agents from proofwork-the402-webhook.phase-voice.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).
Verifies a specific Circle USDC payment on Base mainnet by checking a transaction hash against an expected recipient and amount, returning finalized chain evidence.
Price / call$0.01
Success—
StatusUnknown
How this service works
Small non-cyber evidence and data APIs payable per request with x402 on Base.
Output
Returns a JSON object with a 'verdict' field (e.g. 'confirmed'), a 'confirmed' boolean, a 'finality' field indicating chain finality status (e.g. 'finalized'), an 'evidence' array of supporting on-chain data, and an 'observed' object with raw transaction details. Agents can use 'confirmed: true' and 'finality: finalized' together to conclusively prove payment occurred.
Example use cases
Confirm customer payment before service delivery
“Before I release the digital goods, verify that transaction 0x7f3c2a...d891 sent exactly 49.99 USDC to my wallet 0xDe45...9Abc on Base and that it's finalized.”
Audit trail for automated invoice reconciliation
“I need to confirm that the USDC payment for invoice #1042 went through — the transaction hash is 0xA1b2C3...e4F5, expected recipient is 0x1234...abcd, and the amount should be 200.00 USDC on Base mainnet.”
Dispute resolution for a marketplace transaction
“A buyer claims they paid 75.00 USDC to 0x9876...fedc on Base — can you check transaction 0xBc12...3dEf and tell me if it's confirmed and finalized so I can settle the dispute?”
Technical details
Endpoint
GEThttps://proofwork-the402-webhook.phase-voice.workers.dev/v1/base-usdc-receiptWhen to prefer
Use this endpoint when you need cryptographic, on-chain proof that a specific USDC payment occurred on Base mainnet with exact recipient and amount matching. Prefer it over general blockchain explorers when you need a structured, machine-readable verdict with finality confirmation — ideal for automated payment gating, invoice reconciliation, or dispute resolution in agent workflows where trust in payment receipt must be verifiable without a centralized payment processor.
Side effects
- Transaction hash not found on Base mainnet — returns unconfirmed or error verdict
- Expected amount or recipient does not match on-chain data — returns verdict indicating mismatch
- Transaction exists but is not yet finalized — returns pending finality status
- Malformed transaction hash (not 0x + 64 hex chars) — schema validation error
- Invalid recipient address format — schema validation error
- Amount format exceeds allowed precision or length — validation rejection
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"mode": "inspect",
"verdict": "observed",
"evidence": [],
"finality": "finalized",
"observed": {},
"confirmed": true,
"transaction": {}
}
}Tags
x402
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