# ScanPay x402 quickstart

ScanPay is pay-per-call: request an endpoint, get HTTP 402 with an `accepts` list, sign the
USDC payment that matches one entry, retry with `PAYMENT-SIGNATURE`, and read the JSON plus
the signed `X-Delivery-Receipt`.

## 1. Smoke-test your wallet and an x402 client for $0.0001
POST https://scanpay-edge.alextaghiashvili.workers.dev/api/v1/canary  (or GET with any query)
Body: anything. The response echoes it and returns both network accepts.
This proves signing, facilitator settlement and delivery receipts end to end.

## 2. TypeScript (x402-fetch)
```ts
import { wrapFetchWithPayment, decodeXPaymentResponse } from "x402-fetch";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);
const fetchWithPay = wrapFetchWithPayment(fetch, account);
const res = await fetchWithPay("https://scanpay-edge.alextaghiashvili.workers.dev/api/v1/perp-funding", {
  method: "POST", headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ symbol: "BTC" })
});
const data = await res.json();
const receipt = decodeXPaymentResponse(res.headers.get("x-payment-response") || "");
console.log(data, receipt);
```

## 3. Python (x402 client)
```py
import os, requests
from eth_account import Account
from x402.http.x402_http_client_base import encode_payment_signature_header
from x402.mechanisms.evm.exact.client import ExactEvmScheme
from x402.schemas import PaymentPayload, PaymentRequirements

acct = Account.from_key(os.environ["PRIVATE_KEY"])
url = "https://scanpay-edge.alextaghiashvili.workers.dev/api/v1/canary"
r = requests.post(url, json={"ping": "quickstart"})
quote = r.headers["PAYMENT-REQUIRED"]  # base64 JSON
import base64, json
accept = next(a for a in json.loads(base64.b64decode(quote))["accepts"]
              if a["network"] == "eip155:8453")
req = PaymentRequirements(scheme=accept["scheme"], network=accept["network"],
                          asset=accept["asset"], amount=accept["amount"],
                          pay_to=accept["payTo"],
                          max_timeout_seconds=accept.get("maxTimeoutSeconds", 300),
                          extra=accept.get("extra"))
inner = ExactEvmScheme(acct).create_payment_payload(req)
payload = PaymentPayload(x402_version=2, payload=inner, accepted=req)
r = requests.post(url, json={"ping": "quickstart"},
                  headers={"PAYMENT-SIGNATURE": encode_payment_signature_header(payload)})
print(r.status_code, r.json())
```

## 4. Hero endpoints (see /llms.txt for all 58)
- POST /v1/chat/completions ($0.002) — OpenAI-compatible chat (point an OpenAI base_url at https://scanpay-edge.alextaghiashvili.workers.dev/v1).
- POST /v1/chat/nano ($0.002) — short, high-volume chat.
- POST /api/v1/perp-funding ($0.001) — Binance/Bybit/Hyperliquid funding + arb spread.
- POST /api/v1/crypto-price ($0.001) — spot prices.
- POST /api/v1/web-search ($0.01) — search results.
- POST /api/v1/spl-mint-audit ($0.001) — Solana SPL mint authorities/risk.
- POST /api/v1/receipt-verify ($0.001) — verify a delivery receipt before acting on it.

## 5. Verify what you got
Every paid 200 carries `X-Delivery-Receipt` = base64 of {receipt, attestation}, EIP-191 signed.
POST the receipt to /api/v1/receipt-verify ($0.001) or verify it yourself against
https://scanpay-edge.alextaghiashvili.workers.dev/.well-known/attestation-address. Every response also has `Server-Timing: app;dur=...`.

## 6. Legacy x402 v1 clients (Base only)
If your stack still speaks x402 v1, send the legacy header instead of PAYMENT-SIGNATURE:
  X-PAYMENT: base64({"x402Version":1,"scheme":"exact","network":"base",
                     "payload":{"signature":"0x...","authorization":{...}}})
ScanPay converts it server-side to a v2 payment, settles on Base, and returns both
`X-PAYMENT-RESPONSE` (legacy) and `PAYMENT-RESPONSE` (v2). Solana v1 is not supported yet.

No signup, no API key, no free tier. Base USDC 0x1E04f5046500e5369E17AF993Dc60aC29D83efc9; Solana SPL-USDC N6ZJxx4DAGbDYv3HbVYXso3yFyqprrxPPzdKsZpHHX9.