# Base USDC Receipt Inspector

Paid GET endpoint that decodes a single Base USDC `Transfer` from a transaction hash.

## Endpoint

`GET /v1/usdc-receipt?tx=<0x-transaction-hash>`

## Payment

x402 v2 `exact` native USDC on Base (`eip155:8453`). Price **0.01 USDC** per call to `0xC1123bb365c3e8C7101bEf362bD45D8Bc0F5254A`.

1. Call without payment → HTTP 402 with `PAYMENT-REQUIRED`.
2. Sign the EIP-3009 authorization and retry with `PAYMENT-SIGNATURE`.
3. Response includes `PAYMENT-RESPONSE` with settlement hash when paid.

## Example

```bash
curl -i "https://HOST/v1/usdc-receipt?tx=0x…"
```

Successful JSON fields: `tx`, `status`, `blockNumber`, `transfers[]` with `from`, `to`, `amount_usdc`, `logIndex`.

## Errors

- Missing/invalid `tx` → 400
- Tx not found → 404
- No USDC Transfer logs → 200 with empty `transfers` and `note`
- Unpaid → 402

## Limits

One tx hash per call. Base mainnet only. No signing, broadcasting, or private-key handling.