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Payment Receipts

Find a native Base USDC transfer and return payer, payee, exact amount, time, block, confirmations and OFAC flags in signed JSON with a printable page.

Open Stablecoin Books

Who it’s for

Merchants documenting payment observations, agents retaining evidence and invoice operators.

Price

0.01 USDC per receipt. No free trial.

Paid calls use x402 with USDC on Base. Read the quote before authorizing payment; examples below do not pay automatically.

Know the limits

A signed observation is not invoice ownership, commercial-purpose or irreversible-finality proof. Native Base USDC only. Ambiguous matches fail without charge. Informational, not tax advice.

A 30-second integration

Examples use placeholders. Plain requests to paid tools return a payment challenge, not a paid result. Free Lint can perform an unpaid public probe. Inspect the response status and evidence scope before using any result.

curl

curl -i https://api.spendpreflight.com/v1/books/receipt \
  -H 'Content-Type: application/json' \
  -d '{"tx_hash":"0x1111111111111111111111111111111111111111111111111111111111111111"}'

MCP

Connect to https://api.spendpreflight.com/mcp. Call the existing tool:

{
  "name": "payment_receipt",
  "arguments": {
    "tx_hash": "0x1111111111111111111111111111111111111111111111111111111111111111"
  }
}

SDK / JavaScript

Install spendpreflight@0.3.0 or newer. The helper accepts a caller-supplied, explicitly budgeted payment-capable fetch when you choose to pay.

import { paymentReceipt } from 'spendpreflight';
// plain fetch discovers payment requirements; no wallet or automatic payment
const result = await paymentReceipt({"tx_hash":"0x1111111111111111111111111111111111111111111111111111111111111111"});

Frequently asked questions

What does the signature prove?

It binds the exact observation to a SpendPreflight signing key. Public verification checks signature and hash, not fresh chain state.

Can I find a receipt without a transaction hash?

Use exact pay_to, decimal amount and a past start/end window of up to 90 days. Multiple matches require disambiguation.

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