x402-node-server

x402 + PEAC Integration Example

Demonstrates how PEAC receipts work with x402 HTTP 402 payment flows.

Live demo: x402.peacprotocol.org | Visual demo repo

What This Shows

1. Client requests a protected resource (no receipt)
2. Server returns 402 with x402 v2 payment requirements
3. Client pays via x402 (Base/USDC in this example)
4. Server issues a signed PEAC receipt with x402 evidence
5. Client verifies the receipt offline

The x402 + PEAC Stack

+------------------+     +------------------+
|     Client       |     |     Server       |
+------------------+     +------------------+
         |                        |
         | 1. GET /resource       |
         |----------------------->|
         |                        |
         | 2. 402 Payment-Required|
         |   (x402 v2 headers)    |
         |<-----------------------|
         |                        |
         | 3. Pay via x402        |
         |   (Base/USDC)          |
         |----------------------->|
         |                        |
         | 4. 200 OK              |
         |   PEAC-Receipt: <jws>  |
         |<-----------------------|
         |                        |
         | 5. Verify offline      |
         |   (Ed25519 JWS)        |
+------------------+     +------------------+

x402 v2 Headers

This example uses x402 v2 header format:

HTTP/1.1 402 Payment Required
Content-Type: application/problem+json
Payment-Required: {"network":"eip155:8453","asset":"USDC","amount":"50","recipient":"0x...","resource":"..."}
PEAC-Issuer: https://payment.example.com

The Payment-Required header (v2) replaces the X-PAYMENT header from v1.

PEAC Receipt with x402 Evidence

{
  "typ": "interaction-record+jwt",
  "iss": "https://payment.example.com",
  "aud": "https://api.example.com/premium/data",
  "amt": 50,
  "cur": "USD",
  "payment": {
    "rail": "x402",
    "asset": "USDC",
    "env": "live",
    "reference": "x402_1703001234567",
    "evidence": {
      "network": "eip155:8453",
      "tx_hash": "0xabc123...",
      "recipient": "0x1234...",
      "x402_version": "v2"
    }
  }
}

Prerequisites

From the repository root:

pnpm install
pnpm build

Running the Demo

cd examples/x402-node-server
pnpm demo

Expected output:

=== x402 + PEAC Integration Demo ===

Resource: https://api.example.com/premium/data
Network:  eip155:8453
Price:    $0.50 USDC

1. Client requests protected resource...
   -> 402 Payment Required
   -> Network: eip155:8453
   -> Asset: USDC
   -> Amount: 50

2. Client pays via x402...
   -> Payment confirmed
   -> PEAC receipt issued (xxx chars)

3. Client retries with PEAC-Receipt header...
   -> 200 OK - Access granted!
   -> Data: {"data":"Premium content unlocked via x402 payment","accessedAt":"..."}

4. Verify receipt offline...
   -> Receipt claims:
      iss: https://payment.example.com
      aud: https://api.example.com/premium/data
      amt: 50 USD
      rail: x402
      network: eip155:8453
      tx_hash: 0x...

=== Demo Complete ===

Key Concepts

x402 Handles Payment, PEAC Proves It

• x402 is the payment rail (Base/USDC, Solana, etc.)
• PEAC is the receipt layer (cryptographic proof of payment)

Together they provide:

• Instant payments via crypto rails
• Offline-verifiable receipts
• Audit trail with payment evidence

Supported Networks (CAIP-2)

Network	CAIP-2 ID
Base Mainnet	eip155:8453
Base Sepolia	eip155:84532
Solana Mainnet	solana:mainnet
Solana Devnet	solana:devnet

Receipt Verification

Clients can verify receipts:

1. At request time - Server verifies before granting access
2. Offline - Client verifies signature without network calls
3. Later - Audit systems can verify historical receipts

Production Integration

For production x402 + PEAC integration:

1. Server-side: Use @peac/rails-x402 adapter
2. Discovery: Publish /.well-known/peac.txt with payment terms
3. x402 SDK: Use Coinbase x402 SDK for payment handling

See the x402 ecosystem for compatible tools and services.

No External Dependencies

This example simulates:

• x402 payment confirmation
• PEAC receipt issuance
• Offline verification

No network calls or secrets required.