x402 Payment Protocol
npm install ins402-nextbash
npm install x402-next
`
Quick Start
Create a middleware file in your Next.js project (e.g., middleware.ts):
`typescript
import { paymentMiddleware, Network } from 'x402-next';
export const middleware = paymentMiddleware(
"0xYourAddress",
{
'/protected': {
price: '$0.01',
network: "xlayer",
config: {
description: 'Access to protected content'
}
},
}
);
// Configure which paths the middleware should run on
export const config = {
matcher: [
'/protected/:path*',
]
};
`
Configuration
The paymentMiddleware function accepts three parameters:
1. payTo: Your receiving address (0x${string})
2. routes: Route configurations for protected endpoints
3. facilitator: (Optional) Configuration for the x402 facilitator service
4. paywall: (Optional) Configuration for the built-in paywall
See the Middleware Options section below for detailed configuration options.
Middleware Options
The middleware supports various configuration options:
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`typescript
type RoutesConfig = Record;
interface RouteConfig {
price: Price; // Price in USD or token amount
network: Network; // e.g., "xlayer"
config?: PaymentMiddlewareConfig;
}
`
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`typescript
interface PaymentMiddlewareConfig {
description?: string; // Description of the payment
mimeType?: string; // MIME type of the resource
maxTimeoutSeconds?: number; // Maximum time for payment (default: 60)
outputSchema?: Record; // JSON schema for the response
customPaywallHtml?: string; // Custom HTML for the paywall
resource?: string; // Resource URL (defaults to request URL)
}
`
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`typescript
type FacilitatorConfig = {
url: string; // URL of the x402 facilitator service
createAuthHeaders?: CreateHeaders; // Optional function to create authentication headers
};
`
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For more on paywall configuration options, refer to the paywall README.
`typescript
type PaywallConfig = {
cdpClientKey?: string; // Your CDP Client API Key
appName?: string; // Name displayed in the paywall wallet selection modal
appLogo?: string; // Logo for the paywall wallet selection modal
sessionTokenEndpoint?: string; // API endpoint for Coinbase Onramp session authentication
};
`
Accessing Mainnet with @coinbase/x402
TEMPORARY WORKAROUND: The following configuration changes are only required until the @coinbase/x402 package adds support for Edge runtime. Coinbase is actively working on making the package Edge-compatible, which will eliminate the need for these workarounds in the near future.
To use the official Coinbase facilitator package (@coinbase/x402) in your Next.js project, you'll need to make the following temporary changes to your project configuration:
1. Install the Coinbase facilitator package:
`bash
npm install @coinbase/x402
`
2. Enable Node.js middleware as an experimental feature in your Next.js config:
`ts
// next.config.ts
const nextConfig: NextConfig = {
// rest of your next config setup
experimental: {
nodeMiddleware: true, // TEMPORARY: Only needed until Edge runtime support is added
}
};
export default nextConfig;
`
3. Specify the Node.js runtime in your middleware file:
`ts
// middleware.ts
import { paymentMiddleware } from "x402-next";
import { facilitator } from "@coinbase/x402";
export const middleware = paymentMiddleware(
"0xYourAddress",
{
"/protected": {
price: "$0.01",
network: "base",
// other config options
},
},
facilitator // Use the Coinbase facilitator
);
export const config = {
matcher: ["/protected/:path*"],
runtime: 'nodejs', // TEMPORARY: Only needed until Edge runtime support is added
};
`
4. Update your Next.js dependency to the canary version to access experimental features:
`json
// package.json
{
"dependencies": {
"next": "canary", // TEMPORARY: Only needed until Edge runtime support is added
"x402-next": "^1.0.0",
"@coinbase/x402": "^1.0.0"
// other dependencies
}
}
`
5. Set up your CDP API keys as environment variables:
`bash
.env
CDP_API_KEY_ID=your-cdp-api-key-id
CDP_API_KEY_SECRET=your-cdp-api-key-secret
`
Important Note: Once the @coinbase/x402 package adds support for Edge runtime, you'll be able to use it directly without enforcing the nodejs runtime or requiring the canary version of next.
Optional: Coinbase Onramp Integration
Note: Onramp integration is completely optional. Your x402 paywall will work perfectly without it. This feature is for users who want to provide an easy way for their customers to fund their wallets directly from the paywall.
When configured, a "Get more USDC" button will appear in your paywall, allowing users to purchase USDC directly through Coinbase Onramp.
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#### 1. Configure Your Middleware
Add sessionTokenEndpoint to your middleware configuration. This tells the paywall where to find your session token API:
`typescript
export const middleware = paymentMiddleware(
payTo,
routes,
facilitator,
{
sessionTokenEndpoint: "/api/x402/session-token", // Enable onramp functionality
cdpClientKey: "your-cdp-client-key",
appName: "My App",
}
);
`
Important: The sessionTokenEndpoint can be any path you choose - just make sure it matches where you create your API route in the next step. Without this configuration, the "Get more USDC" button will be hidden.
#### 2. Create the Session Token API
Create an API route that matches the path you configured above:
`typescript
// app/api/x402/session-token/route.ts
export { POST } from "x402-next";
`
That's it! The x402-next package provides the complete session token implementation.
#### 3. Get CDP API Keys
1. Go to CDP Portal
2. Navigate to your project's API Keys
3. Click Create API key
4. Download and securely store your API key
#### 4. Enable Onramp Secure Initialization in CDP Portal
1. Go to CDP Portal
2. Navigate to Payments → Onramp & Offramp
3. Toggle "Enforce secure initialization" to Enabled
#### 5. Set Environment Variables
Add your CDP API keys to your environment:
`bash
.env
CDP_API_KEY_ID=your_secret_api_key_id_here
CDP_API_KEY_SECRET=your_secret_api_key_secret_here
`
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Once set up, your x402 paywall will automatically show a "Get more USDC" button when users need to fund their wallets.
1. Generates session token: Your backend securely creates a session token using CDP's API
2. Opens secure onramp: User is redirected to Coinbase Onramp with the session token
3. No exposed data: Wallet addresses and app IDs are never exposed in URLs
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#### Common Issues
1. "Missing CDP API credentials"
- Ensure CDP_API_KEY_ID and CDP_API_KEY_SECRET are set
- Verify you're using Secret API Keys, not Client API Keys
2. "Failed to generate session token"
- Check your CDP Secret API key has proper permissions
- Verify your project has Onramp enabled
3. API route not found
- Ensure you've created your session token API route at the path you configured
- Check that your API route path matches your sessionTokenEndpoint configuration
- Verify the export: export { POST } from "x402-next";
- Example: If you configured sessionTokenEndpoint: "/api/custom/onramp", create app/api/custom/onramp/route.ts`