Payment Rails

PEAC records what happened during commerce flows. Each rail mapping extracts upstream artifacts, preserves them as-is, and produces a PEAC receipt with typed commerce extensions. PEAC never executes payments, coordinates checkout, or manages wallets.

Supported rails

Rail	Package	What it records	Status
Paymentauth / MPP	@peac/mappings-paymentauth	HTTP 402 challenges, credentials, upstream receipts	Stable
x402	@peac/adapter-x402	Offer/receipt verification, v1/v2 headers, upstream artifact separation	Stable
Stripe	@peac/rails-stripe	Payment intent observation, SPT delegation lifecycle	Source-only
Razorpay	@peac/rails-razorpay	UPI, cards, netbanking, wallets	Source-only
Card networks	@peac/rails-card	Visa, Mastercard, Amex authorization	Source-only

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Paymentauth / MPP

Envelope-first parsing for the HTTP Payment authentication scheme (draft-ryan-httpauth-payment). Extracts Challenge, Credential, and Receipt envelopes with raw artifact preservation.

Terminal

pnpm add @peac/mappings-paymentauth

paymentauth-evidence.ts

import { parsePaymentauthChallenges, parsePaymentauthReceipt } from '@peac/mappings-paymentauth';

// Parse 402 challenges from the WWW-Authenticate header
const challenges = parsePaymentauthChallenges(wwwAuthenticateHeader);

// Parse the upstream receipt from the Payment-Receipt header
const receipt = parsePaymentauthReceipt(paymentReceiptHeader);

Carrier coexistence: PEAC-Receipt (PEAC compact JWS) and Payment-Receipt (upstream receipt) coexist without conflict. JSON-RPC error helpers (-32042, -32043) and MCP extraction functions included.

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x402

Four-layer adapter architecture (A1/A2/B/C) with 5-layer verification API. Reads v1 (X-PAYMENT-RESPONSE) and v2 (PAYMENT-RESPONSE) headers alongside PEAC-Receipt.

Terminal

pnpm add @peac/adapter-x402

x402-evidence.ts

import { extractReceiptArtifactFromHeaders } from '@peac/adapter-x402';

const artifact = extractReceiptArtifactFromHeaders(headers);
// artifact.receipt_jws: PEAC compact JWS only
// artifact.upstreamArtifact: raw upstream data (preserved as-is)
// artifact.artifactFormat: 'peac' | 'x402-v1' | 'x402-v2'

---

Stripe

Payment intent observation and SPT delegation evidence. Commerce event fields are set only when the upstream PaymentIntent explicitly proves the claimed payment state.

Source-only

@peac/rails-stripe is not published to npm in v0.15.0; build it from the repository (packages/rails/stripe).

Payment intent observation

stripe-observation.ts

import { fromStripePaymentIntentObservation } from '@peac/rails-stripe';

const evidence = fromStripePaymentIntentObservation(paymentIntent);
// succeeded -> commerce event: settlement
// requires_capture -> commerce event: authorization
// processing, canceled -> no commerce event

SPT delegation lifecycle

Delegation events record token lifecycle, not payment finality:

Event	Type	Commerce event
delegated_payment_granted	Delegation lifecycle	None
delegated_payment_presented	Delegation lifecycle	None
delegated_payment_deactivated	Delegation lifecycle	None

---

Razorpay

India payment adapter supporting UPI, cards, netbanking, and wallet payments.

Source-only

@peac/rails-razorpay is not published to npm in v0.15.0; build it from the repository (packages/rails/razorpay).

razorpay-evidence.ts

import { normalizeRazorpayPayment, type RazorpayConfig } from '@peac/rails-razorpay';

const config: RazorpayConfig = {
  webhookSecret: process.env.RAZORPAY_WEBHOOK_SECRET!,
};

// event is the verified, parsed webhook payload (after verifyWebhookSignature)
const event = {
  entity: 'event',
  account_id: 'acc_abc123',
  event: 'payment.captured',
  contains: ['payment'],
  payload: {
    payment: {
      entity: {
        id: 'pay_abc123',
        entity: 'payment',
        amount: 1000,
        currency: 'INR',
        status: 'captured',
        order_id: 'order_xyz789',
        international: false,
        method: 'upi',
        amount_refunded: 0,
        captured: true,
        vpa: 'user@upi',
      },
    },
  },
  created_at: 1700000000,
};

const evidence = normalizeRazorpayPayment(event, config);

---

Card networks

Generic card billing bridge for Visa, Mastercard, and Amex.

Source-only

@peac/rails-card is not published to npm in v0.15.0; build it from the repository (packages/rails/card).

card-evidence.ts

import { toPaymentEvidence, type CardBillingEvent } from '@peac/rails-card';

const event: CardBillingEvent = {
  eventId: 'evt_abc123',
  eventType: 'invoice.paid',
  payload: {}, // provider-specific raw event object
  billingSnapshot: {
    provider: 'stripe',
    customerExternalId: 'cus_xyz789',
    planSlug: 'pro-monthly',
    entitlements: [{ feature: 'api-calls', limit: 10000 }],
    capturedAt: '2026-08-11T00:00:00Z',
  },
  amountMinorUnits: 1999,
  currency: 'USD',
  env: 'live',
};

const evidence = toPaymentEvidence(event);

---

Commerce extension (Interaction Record format)

All commerce evidence uses the org.peacprotocol/commerce extension group:

issue-commerce-receipt.ts

import { issue } from '@peac/protocol';

const { jws } = await issue({
  iss: 'https://api.example.com',
  kind: 'evidence',
  type: 'org.peacprotocol/payment',
  pillars: ['commerce'],
  extensions: {
    'org.peacprotocol/commerce': {
      payment_rail: 'stripe',
      amount_minor: '2500',
      currency: 'USD',
      event: 'settlement',
    },
  },
  privateKey: process.env.PEAC_PRIVATE_KEY,
  kid: 'peac-2026-03',
});

The event field is a 6-value closed enum (authorization, settlement, void, refund, chargeback, observation) and is observational metadata only. It records what the upstream system reported, not more.

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Semantic boundary

PEAC mappings preserve raw upstream artifacts and never synthesize payment finality:

• An ACP session "completed" does not prove payment settled
• An SPT "grant" does not prove payment authorized
• A paymentauth receipt proves what the upstream server attested, not more
• event fields are set only when the upstream artifact explicitly proves the claimed state

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Agent Protocols

MCP, ACP, A2A, and UCP protocol mappings.

Express Middleware

Auto-attach receipts to Express.js responses.