@odatano/x402

x402 payment gating for SAP CAP applications, backed by Cardano.

Wire a single before('*') hook into your CAP service. Every gated request returns HTTP 402 Payment Required until the caller proves on-chain settlement. Asset-agnostic: pay in ADA, USDM, or any native asset.

Implements the Cardano-x402-v2 spec on top of @odatano/core.

Install

npm install @odatano/x402 @odatano/core

@odatano/core (the Cardano bridge) is a peer dependency. Install whichever version meets >=1.7.8.

Quick Start

// srv/prices-service.ts
import cds from '@sap/cds';
import { gateService } from '@odatano/x402';

export class PricesService extends cds.ApplicationService {
  async init() {
    gateService(this, {
      payTo:   'addr_test1...your-preprod-address...',
      network: 'cardano:preprod',
      asset:   'lovelace',                // or '<policy>.<nameHex>' for native tokens
      routePricing: {
        Quotes:       '500000',           // 0.5 ADA per Quotes read
        getBestPrice: '1000000',          // 1 ADA per getBestPrice action call
      },
    });
    return super.init();
  }
}

Configure the Cardano backend in package.json:

{
  "cds": {
    "requires": {
      "odatano-core": {
        "network": "preprod",
        "backends": ["blockfrost"],
        "blockfrostApiKey": "preprodXXXXXXXXXXXXXXXXX"
      }
    }
  }
}

cds watch, then probe a gated route: it returns 402 with a v2-shape body. A working example lives in examples/cap-app/.

What's in the box

• gateService(srv, opts) for CAP services and x402Middleware(opts) for plain Express routes.
• x402Fetch / x402Axios wrappers that auto-handle 402 on the client side.
• Facilitator adapter: localFacilitator() (default, in-process via @odatano/core) or httpFacilitator() to delegate verify+settle to a hosted service.
• Helpers: buildUnsignedPaymentTx (browser-buyer flow), verifyConfirmedPayment (post-paid / subscription).

Documentation

Doc	Covers
docs/usage.md	All five usage patterns + full configuration reference
docs/protocol.md	Buyer-flow diagram, PAYMENT-SIGNATURE envelope, the six mandatory facilitator checks
docs/architecture.md	Module layout, pure-vs-chain split, plugin auto-discovery
docs/facilitator-protocol.md	HTTP wire format for the hosted-facilitator pattern (httpFacilitator())
CHANGELOG.md	Versioned changes, latest first

Requirements

• Node.js 22+
• @sap/cds >= 9 (peer)
• @odatano/core >= 1.7.8 (peer)
• express ^4 (peer), only if you use x402Middleware
• A Cardano backend reachable via @odatano/core (Blockfrost / Koios / Ogmios)

Development

npm install                # Workspace install: covers root + examples/*
npm run build              # tsc, emits .js/.d.ts next to .ts (outDir: .)
npm test                   # 232 tests, ~13s

License

Apache-2.0 (see LICENSE)