Sell your API on Sui

import { randomUUID } from "node:crypto";
import { SuiGrpcClient } from "@mysten/sui/grpc";
import { InMemoryDigestStore, USDC } from "@suimpp/mpp";
import {
  createX402Requirements, parseX402Header, settleX402Payment,
  encodeX402Response, X402_PAYMENT_HEADER, X402_PAYMENT_RESPONSE_HEADER,
  X402_VERSION,
} from "@suimpp/mpp/x402";

const PRICE = "0.02";                    // USDC per call
const PAY_TO = "0xYOUR_SUI_ADDRESS";     // step 1
const RESOURCE = "https://api.example.com/v1/search";

const client = new SuiGrpcClient({
  baseUrl: "https://fullnode.mainnet.sui.io",
  network: "mainnet",
});
const store = new InMemoryDigestStore(); // use Redis in production

export async function handler(req: Request): Promise<Response> {
  const header = req.headers.get(X402_PAYMENT_HEADER);

  // No payment → 402 with the envelope.
  if (!header) {
    const [{ chainIdentifier }, state] = await Promise.all([
      client.core.getChainIdentifier(),
      client.core.getCurrentSystemState(),
    ]);
    const requirements = createX402Requirements({
      challengeId: randomUUID(),
      amount: PRICE,
      currency: USDC,
      recipient: PAY_TO,
      resource: RESOURCE,
      network: "mainnet",
      chain: chainIdentifier,
      currentEpoch: state.systemState.epoch,
    });
    return Response.json(
      { x402Version: X402_VERSION, error: "Payment required", accepts: [requirements] },
      { status: 402 },
    );
  }

  // Payment attached → settle FIRST, then serve.
  const payment = parseX402Header(header);
  const settle = await settleX402Payment({
    payment,
    client,
    store,
    expected: {
      challengeId: payment.payload.challengeId,
      amount: PRICE,
      currency: USDC,
      recipient: PAY_TO,
      network: "mainnet",
    },
  });

  const result = { hits: ["…your actual API response…"] }; // your API logic
  return Response.json(result, {
    headers: { [X402_PAYMENT_RESPONSE_HEADER]: encodeX402Response(settle) },
  });
}