@crypto.com/facilitator-client

Official Cronos X402 Facilitator SDK

The Crypto.com Facilitator SDK provides a lightweight, strongly typed Node.js/TypeScript client for interacting with the Cronos X402 Facilitator API. It allows developers to easily:

• Generate EIP-3009 signed payment headers
• Build X402 Payment Requirements
• Submit payments for verification and settlement
• Discover supported networks and capabilities

This SDK enables fully automated off-chain authorization / on-chain execution payments on Cronos Mainnet and Cronos Testnet.

Features

• Facilitator API Client /verify, /settle, /supported

• EIP-3009 Header Generator Produces Base64-encoded X402 payment headers

• Typed X402 Payment Requirements Fully typed and schema-driven

• Zero unnecessary dependencies Built around ethers and native Node features

• Cronos-native Supports Cronos Mainnet and Cronos Testnet

Installation

npm install @crypto.com/facilitator-client
# or
yarn add @crypto.com/facilitator-client

Usage

1. Create a Facilitator Client

The Facilitator base URL is fixed internally and cannot be overridden.

import { Facilitator } from '@crypto.com/facilitator-client';
import { CronosNetwork } from '@crypto.com/facilitator-client';

const facilitator = new Facilitator({
  network: CronosNetwork.CronosTestnet, // or CronosMainnet
});

2. Generate Payment Requirements

const requirements = facilitator.generatePaymentRequirements({
  payTo: '0xRecipientAddress',
  description: 'Payment for Order #123',
  maxAmountRequired: '1000000', // base units
});

console.log(requirements);

3. Generate a Base64 Payment Header (EIP-3009)

import { ethers } from 'ethers';

const signer = new ethers.Wallet(process.env.PRIVATE_KEY!, new ethers.JsonRpcProvider('https://evm-t3.cronos.org'));

const header = await facilitator.generatePaymentHeader({
  to: '0xRecipientAddress',
  value: '1000000', // 1 USDCe (6 decimals)
  signer,
  validBefore: Math.floor(Date.now() / 1000) + 600, // 10 min expiry
});

console.log('header:', header);

4. Verify a Payment Request

const body = facilitator.buildVerifyRequest(header, requirements);

const verifyResponse = await facilitator.verifyPayment(body);
console.log('verify:', verifyResponse);

5. Settle a Verified Payment

const settleResponse = await facilitator.settlePayment(body);
console.log('settled:', settleResponse);

6. Discover Supported Networks & Schemes

const capabilities = await facilitator.getSupported();
console.log(capabilities);

End-to-End Example (Full Flow)

const facilitator = new Facilitator({ network: CronosNetwork.CronosTestnet });

const signer = new ethers.Wallet(PRIVATE_KEY, new ethers.JsonRpcProvider('https://evm-t3.cronos.org'));

const header = await facilitator.generatePaymentHeader({
  to: RECEIVER,
  value: '1000000',
  signer,
});

const requirements = facilitator.generatePaymentRequirements({
  payTo: RECEIVER,
  description: 'Premium API access',
  maxAmountRequired: '1000000',
});

const body = facilitator.buildVerifyRequest(header, requirements);

const verify = await facilitator.verifyPayment(body);

if (verify.isValid) {
  const settle = await facilitator.settlePayment(body);
  console.log('Transaction:', settle.txHash);
}

API Overview

Client

Method	Description
getSupported()	Returns supported networks, schemes, and capabilities
verifyPayment(request)	Validates the Base64 header + requirements
settlePayment(request)	Executes the authorized transfer on-chain
buildVerifyRequest(header, requirements)	Helper to produce valid X402 bodies

Utilities

Function	Description
generatePaymentHeader(options)	Creates Base64 EIP-3009 payment header
generatePaymentRequirements(options)	Produces typed X402 Payment Requirements

License

MIT © 2025 Crypto.com