@xenga/server

Server SDK for xenga escrow payments — middleware, service type registry, and facilitator dispatch. Framework-agnostic core with Express and Next.js adapters.

Install

npm install @xenga/server viem

Quick start

Express middleware

import express from "express";
import { escrowPaymentMiddleware } from "@xenga/server/express";

const app = express();

// Protect any route with xenga escrow payments
app.post("/api/premium",
  escrowPaymentMiddleware({
    facilitatorUrl: "https://facilitator.example.com",
    price: "5000000",        // 5 USDC (6 decimals)
    sellerAddress: "0x...",
    serviceType: "agent-service",
  }),
  (req, res) => {
    // Only reached after payment is verified and settled on-chain
    res.json({ data: "premium content" });
  }
);

Next.js Route Handler

import { handleEscrowPayment, toNextResponse } from "@xenga/server/nextjs";

export async function POST(request: Request) {
  const result = await handleEscrowPayment(request, {
    facilitatorUrl: "https://facilitator.example.com",
    price: "5000000",
    sellerAddress: "0x...",
    serviceType: "marketplace",
  });

  if (result.status === 402) return toNextResponse(result);

  // Payment verified — return content
  return Response.json({ data: "premium content" });
}

Framework-agnostic core

import { processEscrowPayment } from "@xenga/server";
import type { PaymentContext, PaymentDeps } from "@xenga/server";

const result = await processEscrowPayment(context, deps);
// result.status: 200 | 402 | 400 | 500
// result.headers: Record<string, string>
// result.body: object

Service types

Built-in service types define escrow parameters per use case:

import {
  registerServiceType,
  marketplaceServiceType,
  agentServiceType,
} from "@xenga/server";

// Register built-ins
registerServiceType(marketplaceServiceType);  // 7-day release window
registerServiceType(agentServiceType);        // 1-hour release window

// Register custom service type
registerServiceType({
  name: "saas-subscription",
  releaseWindow: 86400,  // 1 day
  autoVerify: false,
  adjustParams(params, reputation) {
    // Shorten window for high-trust counterparties
    if (reputation.sellerScore > 80) {
      return { ...params, releaseWindow: 43200 }; // 12 hours
    }
    return params;
  },
});

Exports

| Import path | Contents | |-------------|----------| | @xenga/server | processEscrowPayment, service type registry, facilitator dispatch | | @xenga/server/express | escrowPaymentMiddleware for Express | | @xenga/server/nextjs | handleEscrowPayment, toNextResponse for Next.js |

Peer dependencies

• viem ^2.21.0
• express ^4.18.0 || ^5.0.0 (optional — only needed for Express adapter)