Add x402 server template

src/lib/choices/framework.ts

@@ -1,7 +1,7 @@
 import { Framework } from '../types/framework';
 
 export const FRAMEWORK_OPTIONS = (
-  Object.keys({ nextjs: null, 'vite-react': null } as Record<
+  Object.keys({ nextjs: null, 'vite-react': null, node: null } as Record<
     Framework,
     null
   >) as Framework[]

src/lib/choices/templates.ts

@@ -49,7 +49,19 @@ const VITE_REACT_TEMPLATE_OPTIONS: ITemplate[] = [
   },
 ];
 
+const NODE_TEMPLATE_OPTIONS: ITemplate[] = [
+  {
+    name: 'x402 Server (ERC-7710)',
+    value: 'x402-server',
+    description:
+      'A Node.js Express server with x402 payment middleware and ERC-7710 support',
+    framework: 'node',
+    isWeb3AuthSupported: false,
+  },
+];
+
 export const TEMPLATE_OPTIONS: ITemplate[] = [
   ...NEXTJS_TEMPLATE_OPTIONS,
   ...VITE_REACT_TEMPLATE_OPTIONS,
+  ...NODE_TEMPLATE_OPTIONS,
 ];

src/lib/types/framework.ts

@@ -1 +1 @@
-export type Framework = 'nextjs' | 'vite-react';
+export type Framework = 'nextjs' | 'vite-react' | 'node';

templates/node/x402-server/.env.example

@@ -0,0 +1,5 @@
+# Address that receives payment for the protected resource
+PAY_TO_ADDRESS=0x...
+
+# Override the default MetaMask Sentinel facilitator URL
+FACILITATOR_URL=https://tx-sentinel-base-mainnet.dev-api.cx.metamask.io/platform/v2/x402

templates/node/x402-server/.gitignore

@@ -0,0 +1,22 @@
+# dependencies
+node_modules/
+
+# build output
+dist/
+
+# env files
+.env
+
+# misc
+.DS_Store
+*.pem
+
+# debug
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+.pnpm-debug.log*
+
+# typescript
+*.tsbuildinfo
+.npmrc

templates/node/x402-server/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "x402-server",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "build": "tsc",
+    "dev": "tsx watch src/index.ts",
+    "start": "node dist/index.js"
+  },
+  "dependencies": {
+    "@x402/core": "^2.12.0",
+    "@x402/evm": "^2.12.0",
+    "@x402/express": "^2.12.0",
+    "cors": "^2.8.5",
+    "dotenv": "^16.4.7",
+    "express": "^4.21.2"
+  },
+  "devDependencies": {
+    "@types/cors": "^2.8.17",
+    "@types/express": "^5.0.2",
+    "@types/node": "^22.15.3",
+    "tsx": "^4.19.4",
+    "typescript": "^5.8.3"
+  }
+}

templates/node/x402-server/src/index.ts

@@ -0,0 +1,62 @@
+import { config } from "dotenv";
+import express, { type Request, type Response } from "express";
+import cors from "cors";
+import { paymentMiddleware } from "@x402/express";
+import { x402ResourceServer, HTTPFacilitatorClient } from "@x402/core/server";
+import { Erc7710ExactEvmScheme } from "./scheme.js";
+
+config();
+
+const NETWORK_ID = "eip155:8453";
+const PORT = 4402;
+
+const payToAddress = process.env.PAY_TO_ADDRESS as string;
+if (!payToAddress) {
+  console.error("PAY_TO_ADDRESS environment variable is required");
+  process.exit(1);
+}
+
+const facilitatorUrl = process.env.FACILITATOR_URL as string;
+if (!facilitatorUrl) {
+  console.error("FACILITATOR_URL environment variable is required");
+  process.exit(1);
+}
+
+const facilitatorClient = new HTTPFacilitatorClient({ url: facilitatorUrl });
+
+const app = express();
+app.use(cors({ exposedHeaders: ["PAYMENT-REQUIRED", "PAYMENT-RESPONSE"] }));
+
+app.use(
+  paymentMiddleware(
+    {
+      "GET /api/hello": {
+        accepts: [
+          {
+            scheme: "exact",
+            price: "$0.01",
+            network: NETWORK_ID,
+            payTo: payToAddress,
+          },
+        ],
+        description: "Access to protected resource",
+        mimeType: "application/json",
+      },
+    },
+    new x402ResourceServer(facilitatorClient).register(
+      NETWORK_ID,
+      new Erc7710ExactEvmScheme(facilitatorClient),
+    ),
+  ),
+);
+
+app.get("/api/hello", (_req: Request, res: Response) => {
+  res.json({ message: "Hello!" });
+});
+
+app.listen(PORT, () => {
+  console.log(`[seller] Server running on http://localhost:${PORT}`);
+  console.log(`[seller] Pay-to address: ${payToAddress}`);
+  console.log(`[seller] Facilitator URL: ${facilitatorUrl}`);
+  console.log(`[seller] Network: ${NETWORK_ID}`);
+});

templates/node/x402-server/src/scheme.ts

@@ -0,0 +1,39 @@
+import { ExactEvmScheme } from "@x402/evm/exact/server";
+import type {
+  PaymentRequirements,
+  SupportedKind,
+} from "@x402/core/types";
+import type { FacilitatorClient } from "@x402/core/server";
+
+export class Erc7710ExactEvmScheme extends ExactEvmScheme {
+  constructor(private readonly facilitatorClient: FacilitatorClient) {
+    super();
+  }
+
+  async enhancePaymentRequirements(
+    paymentRequirements: PaymentRequirements,
+    supportedKind: SupportedKind,
+    facilitatorExtensions: string[],
+  ): Promise<PaymentRequirements> {
+    const enhanced = await super.enhancePaymentRequirements(
+      paymentRequirements,
+      supportedKind,
+      facilitatorExtensions,
+    );
+
+    const supported = await this.facilitatorClient.getSupported();
+    const facilitators = [
+      ...(supported.signers[paymentRequirements.network] ?? []),
+      ...(supported.signers["eip155:*"] ?? [])
+    ];
+
+    return {
+      ...enhanced,
+      extra: {
+        ...enhanced.extra,
+        assetTransferMethod: "erc7710",
+        facilitators,
+      },
+    };
+  }
+}

templates/node/x402-server/tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "esModuleInterop": true,
+    "strict": true,
+    "outDir": "dist",
+    "rootDir": "src",
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "declaration": true
+  },
+  "include": ["src"]
+}