---
title: Express.js Integration
description: Start accepting x402 payments in your Express server in 2 minutes
keywords:
[x402, Express, Node.js, TypeScript, blockchain payments, API monetization]
last_updated: 2026-08-19
---
# Getting Started with Express
Start accepting x402 payments in your Express server in 2 minutes.
:::info Example Code
You can find the full code for this example on [GitHub](https://github.com/BlockEdenHQ/x402-examples/tree/main/typescript/servers/express).
:::
## Step 1: Install Dependencies
Install the required packages for your Express server:
```bash
npm install x402 express dotenv
```
Or with other package managers:
```bash
# pnpm
pnpm add x402 express dotenv
# yarn
yarn add x402 express dotenv
# bun
bun add x402 express dotenv
```
## Step 2: Set Your Environment Variables
Open your generated project's `.env` and set:
- `FACILITATOR_URL`: Facilitator base URL (defaults to: `https://x402.bex.co`)
- `NETWORK`: Network to use for the facilitator (default: `sui`)
- `ADDRESS`: Wallet public address to receive payments to
- `BEX_API_KEY`: Your bex.co API key from [dashboard](https://bex.co/dash/)
```env
FACILITATOR_URL=https://x402.bex.co
NETWORK=sui
ADDRESS=0x... # wallet public address you want to receive payments to
BEX_API_KEY=your_api_key_here
```
:::tip Network Options
bex.co supports multiple networks:
- `sui` (recommended for fastest settlement)
- `ethereum`
- `base`
- `polygon`
- `avalanche`
:::
## Step 3: Create Your Express Server
Create an `index.ts` file with the following code:
```typescript
import { config } from "dotenv";
import express from "express";
import { paymentMiddleware, Network, Resource } from "x402-express";
config();
const facilitatorUrl = process.env.FACILITATOR_URL as Resource;
const payTo = process.env.ADDRESS as `0x${string}`;
const network = process.env.NETWORK as Network;
const apiKey = process.env.BEX_API_KEY;
if (!facilitatorUrl || !payTo || !apiKey || !network) {
console.error("Missing required environment variables");
process.exit(1);
}
const app = express();
app.use(
paymentMiddleware(
payTo,
{
"GET /weather": {
// USDC amount in dollars
price: "$0.001",
network,
},
"/premium/*": {
// Define atomic amounts in any supported token
price: {
amount: "100000",
asset: {
address: "0xabc",
decimals: 18,
name: "USDC",
},
},
network,
},
},
{
url: facilitatorUrl,
apiKey: apiKey,
},
),
);
app.get("/weather", (req, res) => {
res.send({
report: {
weather: "sunny",
temperature: 70,
},
});
});
app.get("/premium/content", (req, res) => {
res.send({
content: "This is premium content",
});
});
app.listen(4021, () => {
console.log(`Server listening at http://localhost:4021`);
});
```
## Step 4: Run the Server
```bash
npx tsx index.ts
```
Or add a script to your `package.json`:
```json
{
"scripts": {
"dev": "tsx watch index.ts",
"start": "node dist/index.js"
}
}
```
Then run:
```bash
npm run dev
```
Your server is now accepting 402 payments!
## Step 5: Test the Server
You can test payments against your server locally using HTTP clients like `curl`, Postman, or by building a client application.
:::note Coming Soon
Client implementation guides for fetch API and axios will be available soon.
:::
## Payment Configuration Options
The `paymentMiddleware` accepts flexible payment configurations:
### Simple Dollar Amount
```typescript
"GET /weather": {
price: "$0.001",
network: "sui",
}
```
### Atomic Token Amount
```typescript
"/premium/*": {
price: {
amount: "100000",
asset: {
address: "0x...",
decimals: 6,
name: "USDC",
},
},
network: "sui",
}
```
### Route Patterns
You can use wildcards and specific HTTP methods:
```typescript
{
"GET /weather": { /* ... */ }, // Exact GET route
"/premium/*": { /* ... */ }, // Any method, wildcard path
"POST /api/analyze": { /* ... */ }, // Exact POST route
}
```
## Advanced Features
### Custom Payment Verification
```typescript
app.use(
paymentMiddleware(payTo, paymentConfig, {
url: facilitatorUrl,
apiKey: apiKey,
onPaymentVerified: (req, paymentData) => {
console.log("Payment verified:", paymentData.txHash);
// Custom logging or analytics
},
}),
);
```
### Error Handling
```typescript
app.use((err, req, res, next) => {
if (err.name === "X402PaymentError") {
res.status(402).json({
error: "Payment required",
details: err.message,
});
} else {
next(err);
}
});
```
## Production Deployment
Before deploying to production:
1. Switch to production facilitator endpoint
2. Use production network (e.g., `sui` instead of `sui-testnet`)
3. Enable HTTPS for your server
4. Set up proper error logging
5. Configure CORS if serving cross-origin clients
```typescript
// Production configuration
const app = express();
// Enable CORS
app.use(
cors({
origin: process.env.ALLOWED_ORIGINS?.split(","),
credentials: true,
}),
);
// Use production network
app.use(
paymentMiddleware(
payTo,
{
"GET /weather": {
price: "$0.01",
network: "sui", // Production Sui network
},
},
{
url: "https://x402.bex.co",
apiKey: process.env.BEX_API_KEY,
},
),
);
```
## Troubleshooting
### Common Issues
**Payment verification fails**
- Verify your `BEX_API_KEY` is correct
- Check that the wallet address format matches the network
- Ensure the facilitator URL is accessible
**CORS errors**
- Add CORS middleware before payment middleware
- Configure allowed origins properly
**Network mismatch**
- Ensure client and server use the same network
- Check that the token address is valid for the network
## Next Steps
- [Implement a crypto paywall](./implement-a-crypto-paywall-with-x402.md)
- [View the merchant introduction](./x402-for-merchants.md)
- [Read the Quick Start Guide](./quickstart.md)
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