x402x-facilitator

npm i x402x-facilitator

import { Facilitator } from "x402x-facilitator";
const f = new Facilitator({ recipientAddress: "0xSeller", waitUntil: "confirmed" });
await f.verify(payload, requirements);
await f.settle(payload, requirements);         // returns transaction hash
const supported = await f.supported();         // { kinds, networks, ... }

type VerifyResponse = { success: boolean; payer?: string; error?: string };
type SettleResponse = { success: boolean; transactionHash?: string; error?: string };

type WaitUntil = "simulated" | "submitted" | "confirmed";
// - simulated: only simulate (fastest)
// - submitted: wait until submitted to mempool (fast)
// - confirmed: wait for on-chain confirmation (safest; default in prod)

class Facilitator {
  constructor(config: {
    recipientAddress: string;
    relayer?: string;
    waitUntil?: "simulated" | "submitted" | "confirmed";
    baseUrl?: string;
    apiKey?: string;
  });
  verify(payload: PaymentPayload, requirements: PaymentRequirements): Promise<{
    success: boolean; payer?: string; error?: string;
  }>;
  settle(
    payload: PaymentPayload,
    requirements: PaymentRequirements,
    waitUntil?: "simulated" | "submitted" | "confirmed"
  ): Promise<{ success: boolean; transactionHash?: string; error?: string }>;
  supported(filters?: { chainId?: number; tokenAddress?: string }): Promise<{ kinds: string[] }>;
  getConfig(): Required<FacilitatorConfig>;
}

const verifyResult = await f.verify(payload, requirements);
if (!verifyResult.success) throw new Error(verifyResult.error);

const settleResult = await f.settle(payload, requirements); // third param can override waitUntil
if (!settleResult.success) throw new Error(settleResult.error);

console.log("payer:", verifyResult.payer, "tx:", settleResult.transactionHash);

const result = await f.verify(payload, requirements);
if (result.success) {
  // Validate user intent only; no on-chain transaction
  await grantAccess(result.payer!);
}

const getWait = (amount: string) => BigInt(amount) > BigInt("10000000") ? "confirmed" : "submitted";
const waitUntil = getWait(requirements.maxAmountRequired);
const settled = await f.settle(payload, requirements, waitUntil);