@nanosession/facilitator

Server-side facilitator handler for x402 NanoSession — verifies and settles Nano payments for HTTP 402 flows.

Installation

pnpm add @nanosession/facilitator

Peer dependencies: @nanosession/core, @nanosession/rpc

Usage

import { NanoSessionFacilitatorHandler } from '@nanosession/facilitator';
import { NanoRpcClient } from '@nanosession/rpc';

const rpcClient = new NanoRpcClient({ endpoints: ['https://rpc.nano.to'] });

const facilitator = new NanoSessionFacilitatorHandler({
  rpcClient,
  payTo: 'nano_3your_receiving_address...',
  resourceAmountRaw: '1000000000000000000000000', // 0.001 XNO
});

// Issue payment requirements for a 402 response
const requirements = await facilitator.createRequirements();

// Verify and settle an incoming payment
const result = await facilitator.settle(paymentPayload);

API

NanoSessionFacilitatorHandler

Methods

• createRequirements() — Generates session-bound payment requirements to include in a 402 response
• verify(payload) — Verifies a payment without marking the block hash as spent
• settle(payload) — Verifies and settles a payment (marks block hash as spent, preventing reuse)

Security

NanoSessionFacilitatorHandler uses session binding to prevent receipt-stealing attacks — each set of payment requirements includes a unique session ID and tag amount that the client must encode into the Nano send block. An internal spent set ensures every block hash can only be accepted once, eliminating replay and double-spend attacks.

Documentation

Full protocol specification and guides: https://csi.ninzin.net/x402.NanoSession/

License

MIT