Sign-In-With-X (SIWX)

import {
  declareSIWxExtension,
  createSIWxResourceServerExtension,
  InMemorySIWxStorage,
} from '@x402/extensions/sign-in-with-x';
import { x402ResourceServer } from '@x402/core/server';
import { HTTPFacilitatorClient } from '@x402/core/http';
import { ExactEvmScheme } from '@x402/evm/exact/server';

const NETWORK = 'eip155:8453'; // Base mainnet
const payTo = '0xYourAddress';

// Storage for tracking paid addresses
const storage = new InMemorySIWxStorage();

const facilitatorClient = new HTTPFacilitatorClient({
  url: 'https://x402.org/facilitator'
});

// 1. Register extension
const resourceServer = new x402ResourceServer(facilitatorClient)
  .register(NETWORK, new ExactEvmScheme())
  .registerExtension(createSIWxResourceServerExtension({ storage }));

// 2. Declare SIWX support in routes
const routes = {
  'GET /data': {
    accepts: [{
      scheme: 'exact',
      price: '$0.01',
      network: NETWORK,
      payTo
    }],
    extensions: declareSIWxExtension({
      statement: 'Sign in to access your purchased content',
    }),
  },
  'GET /profile': {
    accepts: [],  // Auth-only route: no payment required
    extensions: declareSIWxExtension({
      network: NETWORK,  // Required for auth-only routes (cannot be inferred from accepts)
      statement: 'Sign in to view your profile',
      expirationSeconds: 300,
    }),
  },
};

import { createPublicClient, http } from 'viem';
import { base } from 'viem/chains';

const publicClient = createPublicClient({
  chain: base,
  transport: http()
});

const resourceServer = new x402ResourceServer(facilitatorClient)
  .register(NETWORK, new ExactEvmScheme())
  .registerExtension(createSIWxResourceServerExtension({
    storage,
    verifyOptions: { evmVerifier: publicClient.verifyMessage },
  }));

import {
  createSIWxSettleHook,
  createSIWxRequestHook,
  InMemorySIWxStorage,
} from '@x402/extensions/sign-in-with-x';
import { x402ResourceServer } from '@x402/core/server';
import { x402HTTPResourceServer } from '@x402/core/http';

const storage = new InMemorySIWxStorage();

// Attach settle hook to record payments after settlement
const resourceServer = new x402ResourceServer(facilitatorClient)
  .register(NETWORK, new ExactEvmScheme())
  .onAfterSettle(createSIWxSettleHook({ storage }));

// Attach request hook to validate SIWX proofs on incoming requests
const httpServer = new x402HTTPResourceServer(resourceServer, routes)
  .onProtectedRequest(createSIWxRequestHook({ storage }));

import { createSIWxClientHook } from '@x402/extensions/sign-in-with-x';
import { x402HTTPClient } from '@x402/fetch';
import { privateKeyToAccount } from 'viem/accounts';

const signer = privateKeyToAccount(process.env.EVM_PRIVATE_KEY as `0x${string}`);

const httpClient = new x402HTTPClient(client)
  .onPaymentRequired(createSIWxClientHook(signer));

import {
  declareSIWxExtension,
  parseSIWxHeader,
  validateSIWxMessage,
  verifySIWxSignature,
  SIGN_IN_WITH_X,
} from '@x402/extensions/sign-in-with-x';

// 1. Declare in PaymentRequired response
const extensions = {
  [SIGN_IN_WITH_X]: declareSIWxExtension({
    domain: 'api.example.com',
    resourceUri: 'https://api.example.com/data',
    network: 'eip155:8453',
    statement: 'Sign in to access your purchased content',
  }),
};

// 2. Verify incoming proof
async function handleRequest(request: Request) {
  const header = request.headers.get('SIGN-IN-WITH-X');
  if (!header) return; // No auth provided

  // Parse the header
  const payload = parseSIWxHeader(header);

  // Validate message fields (expiry, nonce, domain, etc.)
  const validation = await validateSIWxMessage(
    payload,
    'https://api.example.com/data'
  );
  if (!validation.valid) {
    return { error: validation.error };
  }

  // Verify signature and recover address
  const verification = await verifySIWxSignature(payload);
  if (!verification.valid) {
    return { error: verification.error };
  }

  // verification.address is the verified wallet
  // Grant access for auth-only routes or if wallet has paid
  const isAuthOnly = await checkIfAuthOnlyRoute(request);
  const hasPaid = await checkPaymentHistory(verification.address);
  if (isAuthOnly || hasPaid) {
    // Grant access
  }
}

import { createSIWxClientExtension } from '@x402/extensions/sign-in-with-x';
import { x402HTTPClient } from '@x402/fetch';
import { x402Client } from '@x402/core/client';
import { privateKeyToAccount } from 'viem/accounts';

const signer = privateKeyToAccount(process.env.EVM_PRIVATE_KEY as `0x${string}`);
const client = new x402Client();

client.registerExtension(createSIWxClientExtension({ signers: [signer] }));
const httpClient = new x402HTTPClient(client);

// Requests automatically use SIWX auth when server supports it
const response = await httpClient.fetch('https://api.example.com/data');

import {
  createSIWxPayload,
  encodeSIWxHeader,
} from '@x402/extensions/sign-in-with-x';

// 1. Get extension and network from 402 response
const paymentRequired = await response.json();
const extension = paymentRequired.extensions['sign-in-with-x'];
const paymentNetwork = paymentRequired.accepts[0].network; // e.g., "eip155:8453"

// 2. Find matching chain in supportedChains
const matchingChain = extension.supportedChains.find(
  chain => chain.chainId === paymentNetwork
);

if (!matchingChain) {
  throw new Error('Chain not supported');
}

// 3. Build complete info with selected chain
const completeInfo = {
  ...extension.info,
  chainId: matchingChain.chainId,
  type: matchingChain.type,
};

// 4. Create signed payload
const payload = await createSIWxPayload(completeInfo, signer);

// 5. Encode and send
const header = encodeSIWxHeader(payload);
const response = await fetch(url, {
  headers: { 'SIGN-IN-WITH-X': header }
});

const routes = {
  'GET /data': {
    accepts: [
      {
        scheme: 'exact',
        price: '$0.01',
        network: 'eip155:8453', // Base
        payTo: '0xYourAddress'
      },
      {
        scheme: 'exact',
        price: '$0.01',
        network: 'solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp', // Solana mainnet
        payTo: 'YourSolanaAddress'
      }
    ],
    extensions: declareSIWxExtension({
      network: ['eip155:8453', 'solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp'],
      statement: 'Sign in to access your purchased content',
    }),
  },
};