Verifiable Receipts for
Paid API Calls

Every 200 OK comes with a cryptographic receipt.
Pay with x402 (Base/USDC) → Get proof of what you bought, from whom, under which policy.

Try Shop DemoAgent APIHow It Works
PEAC Protocol·peac.txt·AIPREF·OpenAPI·GitHub
HTTP 402
Payment Required → x402 → Receipt
EdDSA
Cryptographically signed receipts
Base/USDC
On-chain payments, verifiable proofs

How It Works

1

Discovery

Agent reads /.well-known/peac.txt to learn payment options, receipt policy, and public keys

2

HTTP 402

API returns 402 Payment Required with session_id and amount (e.g., $0.05 USDC)

3

Pay via x402

Agent pays on Base with USDC, gets proof_id from facilitator

4

Get Receipt

200 OK with PEAC-Receipt header: cryptographic proof of purchase, verifiable forever

Agent-to-Agent Commerce

Autonomous agents can discover, purchase, and verify digital goods using machine-readable APIs.

Discovery

Start with /.well-known/peac.txt to learn payment options and policies.

View peac.txt →

OpenAPI Spec

Complete API documentation with schemas, endpoints, and examples.

View OpenAPI →

Documentation

curl examples, headless buyer agent code, receipt format details.

View Docs →

Stateless Checkout Endpoint

POST /api/shop/checkout-direct

No cart state required. Send items array, get 402 → pay via x402 → retry with proof → receive cryptographic receipt.

# Step 1: Attempt checkout
curl -X POST /api/shop/checkout-direct \
-d '{"items":[{"sku":"sku_tea","qty":1}]}'
# Step 2: Get session_id from 402 response, pay via x402
# Step 3: Retry with proof
curl -X POST /api/shop/checkout-direct \
-H "X-402-Session: $TOKEN" \
-H "X-402-Proof: $PROOF_ID" \
-d '{"items":[{"sku":"sku_tea","qty":1}]}'

Works with Coinbase Payments MCP

NEW

MCP pays. PEAC proves. Coinbase Payments MCP equips agents with wallets and x402 payment capability. Our API issues cryptographic receipts that prove what agents bought - portable, policy-bound, and independently verifiable.

Install Payments MCP

npx @coinbase/payments-mcp

Give your agents an embedded wallet, USDC onramp, and automatic x402 payment capability. Works with Claude Desktop, Gemini CLI, and any MCP-compatible client.

Integration Flow

  1. 1.Agent calls /api/shop/checkout-direct
  2. 2.Receives 402 Payment Required
  3. 3.MCP pays automatically via x402 (USDC on Base)
  4. 4.Agent retries with proof
  5. 5.Receives 200 OK + PEAC-Receipt (EdDSA-signed JWS)
  6. 6.Receipt proves: payment made, content delivered, policy bound

Try It in Claude Desktop

> "Buy 1 tea from https://x402.peacprotocol.org/api/shop/checkout-direct and show me the receipt"

With Payments MCP installed, Claude will automatically discover payment requirements, pay via x402, and receive the cryptographic PEAC-Receipt - all autonomously.

Payments MCP Docs →MCP Server with x402 →Integration Guide →

Why PEAC Receipts?

Portable Proofs

Receipts are self-contained JWS tokens. Verify anywhere with the public key.

Policy-Bound

Every receipt embeds the AIPREF snapshot: license terms, retention, refund policy.

Content Integrity

Response body SHA256 hash proves you got exactly what you paid for.

Rail-Agnostic

x402 today. Same receipt format works with any future payment rail.

Try It Now

Complete a real checkout with $0.05 USDC demo payment,
get a cryptographic receipt, verify it instantly.

Open Shop DemoVerify Offline