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@sei-js/x402-hono

Hono middleware integration for the x402 Payment Protocol. This package allows you to easily add paywall functionality to your Hono applications using the x402 protocol.

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Installation

npm install @sei-js/x402-hono

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Quick Start

import { Hono } from "hono";
import { paymentMiddleware, Network } from "@sei-js/x402-hono";

const app = new Hono();

// Configure the payment middleware
app.use(paymentMiddleware(
  "0xYourAddress",
  {
    "/protected-route": {
      price: "$0.10",
      network: "sei",
      config: {
        description: "Access to premium content",
      }
    }
  }
));

// Implement your route
app.get("/protected-route", (c) => {
  return c.json({ message: "This content is behind a paywall" });
});

serve({
  fetch: app.fetch,
  port: 3000
});

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Configuration

The paymentMiddleware function accepts three parameters:
  1. payTo: Your receiving address (0x${string})
  2. routes: Route configurations for protected endpoints
  3. facilitator: (Optional) Configuration for the x402 facilitator service
  4. paywall: (Optional) Configuration for the built-in paywall

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Middleware Options

The middleware supports the same configuration options as the Express middleware:

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Route Configuration

type RoutesConfig = Record<string, Price | RouteConfig>;

interface RouteConfig {
  price: Price;           // Price in USD or token amount
  network: Network;       // "sei" or "seiTestnet"
  config?: PaymentMiddlewareConfig;
}

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Payment Configuration

interface PaymentMiddlewareConfig {
  description?: string;               // Description of the payment
  mimeType?: string;                  // MIME type of the resource
  maxTimeoutSeconds?: number;         // Maximum time for payment (default: 60)
  outputSchema?: Record<string, any>; // JSON schema for the response
  customPaywallHtml?: string;         // Custom HTML for the paywall
  resource?: string;                  // Resource URL (defaults to request URL)
}

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Example with Cloudflare Workers

import { Hono } from "hono";
import { paymentMiddleware } from "@sei-js/x402-hono";

const app = new Hono();

app.use(paymentMiddleware(
  "0xYourAddress",
  {
    "/api/premium": {
      price: "$0.02",
      network: "sei",
      config: {
        description: "Premium API endpoint",
        maxTimeoutSeconds: 60,
      }
    }
  }
));

app.get("/api/premium", (c) => {
  return c.json({
    message: "This is premium content",
    data: {
      timestamp: Date.now(),
      premium: true
    }
  });
});

app.get("/", (c) => {
  return c.text("Hono x402 API Server");
});

export default app;

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Edge Runtime Support

Hono’s lightweight design makes it perfect for edge computing environments. The x402-hono middleware works seamlessly with:
  • Cloudflare Workers
  • Vercel Edge Functions
  • Deno Deploy
  • Bun runtime

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Performance Benefits

  • Minimal overhead: Hono’s fast routing combined with x402’s efficient payment protocol
  • Edge-optimized: Perfect for serverless and edge computing environments
  • TypeScript-first: Full type safety for payment configurations and responses