x402 Facilitator Proxy

Name: x402 Facilitator Proxy
Author: seob5285-alt

by seob5285-altversion 1.0.1i★ –iRuns on your computer

Registry nameio.github.seob5285-alt/x402-facilitator-proxy

Install

Overview

Description from the maker (original English)

Multi-tenant HTTP 402 infrastructure gateway and stdio MCP server for machine payments.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiVery new↓ 57/wk · ★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Developer tools

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
The registry lists no key to fill in.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "x402-facilitator-proxy": {
      "command": "npx",
      "args": [
        "-y",
        "x402-facilitator-proxy"
      ]
    }
  }
}

Run this in your terminal

claude mcp add x402-facilitator-proxy -- npx -y x402-facilitator-proxy

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "x402-facilitator-proxy": {
      "command": "npx",
      "args": [
        "-y",
        "x402-facilitator-proxy"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "x402-facilitator-proxy": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "x402-facilitator-proxy"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 9, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account seob5285-alt, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Developer toolsi

More stars than 0% of the other 5570 servers in this category
Published to the registry more recently than 22% of the other 5570 servers in this category
Basic checks equal to or better than 100% of the other 5570 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is x402 Facilitator Proxy safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (1.0.1) reached the registry 4 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: GitHub, Desktop Commander, Cloudflare MCP

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:↓ Downloads per weeki★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

GitHub

GitHub’s official server lets AI read and manage code, issues and pull requests in your account. Use GitHub’s hosted version or run it locally with Docker.

by githubWidely used★ 34.2KUpdated 6 days ago

Computer or cloud

Install

Desktop Commander

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Cloudflare MCP

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Runs in the cloud✓ mcp.cloudflare.com

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

X402 Facilitator Proxy - Multi-Tenant Payment Gateway

A decentralized, autonomous payment infrastructure for API monetization on Base L2 with programmatic fee routing and agent-compatible settlement protocols.

🏗️ Architecture Overview

The X402 Facilitator Proxy implements a complete multi-tenant payment gateway that enables merchants to monetize APIs through HTTP 402 "Payment Required" responses, while autonomous agents can seamlessly settle transactions using USDC on Base L2.

x402-facilitator-proxy/

├── src/ # Core Cloudflare Worker Engine │ ├── index.ts # Main proxy gateway endpoint │ └── backend/automation/ │ └── sweeper.ts # Automated fee collection ├── x402-client-sdk/ # Core Interface Rails │ ├── src/ │ │ ├── client-library.ts # TypeScript SDK │ │ └── mcp-server.ts # Model Context Protocol Server │ ├── package.json # SDK dependencies │ └── tsconfig.json # TypeScript configuration └── templates/ # Integration Templates ├── express-middleware/ │ └── x402-guard.js # Merchant-Side API Gating ├── langchain-ts/ │ ├── agent.ts # TypeScript Agent Template │ ├── package.json # LangChain dependencies │ └── README.md # Setup instructions └── crewai-python/ └── agent.py # Python Agent Template

🚀 Core Components

1. Cloudflare Worker Proxy Engine

The core backend (src/index.ts) operates as a serverless payment verification gateway deployed on Cloudflare's edge network:

Endpoint: https://x402-facilitator-proxy.seob5285.workers.dev/api/v1/verify-and-settle
Platform Vault: 0x2E3DADfb314718849A93c49A78618E586c3b2C60
Fee Structure: Automated 1% platform fee routing

Key Features:

Multi-tenant transaction verification
Base L2 USDC settlement validation
Automated fee splitting (99% to merchant, 1% to platform)
Edge-deployed for global low-latency access

2. Model Context Protocol (MCP) Server

The MCP server (x402-client-sdk/src/mcp-server.ts) provides a standardized interface for AI agents to interact with the payment system:

# Start the MCP server locally via stdio

npm run mcp:start

Protocol Features:

Standard I/O communication interface
Agent-compatible payment tool registration
Automatic transaction handling and verification
Cross-platform AI framework compatibility

3. Merchant-Side API Gating

The Express middleware (templates/express-middleware/x402-guard.js) enables merchants to protect APIs with HTTP 402 challenges:

import { x402TollboothGuard } from './templates/express-middleware/x402-guard.js';

app.use('/api/premium', x402TollboothGuard("0.10", "0xYourWalletAddress"));

Middleware Behavior:

Challenge: Returns HTTP 402 with payment instructions when headers are missing
Verification: Validates payment through the proxy gateway
Access: Grants API access upon successful payment verification

4. Autonomous Agent Templates

TypeScript/LangChain Agent (`templates/langchain-ts/agent.ts`)

import { createPaymentAgent } from './templates/langchain-ts/agent.js';

const agent = await createPaymentAgent(); const result = await agent.invoke({ input: JSON.stringify({ agentPrivateKey: process.env.AGENT_PRIVATE_KEY, developerWallet: "0x742d35Cc6297C24aE0E4838C4667C02693C4cB36", amountUSD: "0.10" }) });

Python/CrewAI Agent (`templates/crewai-python/agent.py`)

from templates.crewai_python.agent import X402PaymentAgent

agent = X402PaymentAgent() result = agent.process_payment({ "agent_private_key": os.getenv("AGENT_PRIVATE_KEY"), "developer_wallet": "0x742d35Cc6297C24aE0E4838C4667C02693C4cB36", "amount_usd": "0.10" })

🔧 Quick Start

1. Deploy the Proxy Engine

npm install

npm run deploy

2. Setup the MCP Server

cd x402-client-sdk

npm install npm run mcp:start

3. Integrate Merchant Middleware

# Copy the Express middleware to your project

cp templates/express-middleware/x402-guard.js your-project/middleware/

Install in your Express app

import { x402TollboothGuard } from './middleware/x402-guard.js'; app.use('/api/protected', x402TollboothGuard("0.05", "0xYourWallet"));

4. Setup Agent Templates

# For TypeScript/LangChain agents

cd templates/langchain-ts npm install npm run dev

For Python/CrewAI agents

cd templates/crewai-python pip install -r requirements.txt python agent.py

🔐 Security & Environment Variables

Critical Security Guidelines

⚠️ NEVER HARDCODE PRIVATE KEYS IN REPOSITORY FILES

All sensitive credentials must be managed through secure environment variables:

Cloudflare Worker Environment (Production)

# Set via Cloudflare Workers dashboard or wrangler

wrangler secret put FACILITATOR_PRIVATE_KEY wrangler secret put PLATFORM_VAULT_ADDRESS

Local Development Environment

Create .env files for local testing:

# .env (root directory - for Cloudflare Worker development)

FACILITATOR_PRIVATE_KEY=0x1234567890abcdef... PLATFORM_VAULT_ADDRESS=0x2E3DADfb314718849A93c49A78618E586c3b2C60

Agent execution environments

AGENT_PRIVATE_KEY=0xabcdef1234567890... OPENAI_API_KEY=sk-...

Agent Runtime Security

TypeScript Agents: Use process.env.AGENT_PRIVATE_KEY
Python Agents: Use os.getenv("AGENT_PRIVATE_KEY")
MCP Server: Loads keys from system environment at runtime

🌐 Platform Reference

Core Infrastructure

Verification Gateway: https://x402-facilitator-proxy.seob5285.workers.dev/api/v1/verify-and-settle
Platform Vault: 0x2E3DADfb314718849A93c49A78618E586c3b2C60
Network: Base L2 (Chain ID: 8453)
Payment Token: USDC (0x833589fCD6eDb6E08f4c7C32d4f71b54bda02913)

Fee Structure

Merchant Revenue: 99% of payment amount
Platform Fee: 1% automatically routed to platform vault
Gas Optimization: Batched transfers for cost efficiency

📖 Integration Patterns

HTTP 402 Payment Flow

API Request: Client attempts to access protected endpoint
Payment Challenge: Server responds with HTTP 402 and payment instructions
Agent Processing: Autonomous agent detects 402, executes USDC payment split
Verification: Proxy gateway validates on-chain transaction
Access Granted: Original API request succeeds with payment headers

Agent Integration Workflow

graph TD

A[Agent API Call] --> B{HTTP 402?} B -->|Yes| C[Parse Payment Requirements] C --> D[Execute USDC Split Transfer] D --> E[Submit to Proxy Gateway] E --> F[Retry Original Request] F --> G[Access Granted] B -->|No| G

🛠️ Development Commands

# Core proxy development

npm run dev # Start local development server npm run deploy # Deploy to Cloudflare Workers npm run cf-typegen # Generate Cloudflare types

SDK development

cd x402-client-sdk npm run build # Build TypeScript SDK npm run mcp:start # Start MCP server

Template testing

cd templates/langchain-ts npm run dev # Test TypeScript agent

cd templates/crewai-python python agent.py # Test Python agent

Automated fee collection

npm run sweep # Execute fee sweeping automation

📚 Documentation

[Client Integration Guide](CLIENT_INTEGRATION.md): Detailed integration instructions
[LangChain Template README](templates/langchain-ts/README.md): TypeScript agent setup
[API Reference](src/index.ts): Core gateway endpoints and responses

🤝 Contributing

Fork the repository
Create feature branches for new integrations
Test against Base L2 testnet before mainnet deployment
Submit pull requests with comprehensive test coverage

📄 License

This project is licensed under the MIT License - enabling open-source innovation while maintaining platform sustainability through programmatic fee routing.

Built for the autonomous economy. Powered by Base L2. Secured by multi-tenant verification.

x402 Facilitator Proxy

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Developer toolsi

Common questions

Alternatives

GitHub

Desktop Commander

Cloudflare MCP

README from the maker

X402 Facilitator Proxy - Multi-Tenant Payment Gateway

🏗️ Architecture Overview

🚀 Core Components

1. Cloudflare Worker Proxy Engine

2. Model Context Protocol (MCP) Server

3. Merchant-Side API Gating

4. Autonomous Agent Templates

TypeScript/LangChain Agent (templates/langchain-ts/agent.ts)

Python/CrewAI Agent (templates/crewai-python/agent.py)

🔧 Quick Start

1. Deploy the Proxy Engine

2. Setup the MCP Server

3. Integrate Merchant Middleware

Install in your Express app

4. Setup Agent Templates

For Python/CrewAI agents

🔐 Security & Environment Variables

Critical Security Guidelines

Cloudflare Worker Environment (Production)

Local Development Environment

Agent execution environments

Agent Runtime Security

🌐 Platform Reference

Core Infrastructure

Fee Structure

📖 Integration Patterns

HTTP 402 Payment Flow

Agent Integration Workflow

🛠️ Development Commands

SDK development

Template testing

Automated fee collection

📚 Documentation

🤝 Contributing

📄 License

TypeScript/LangChain Agent (`templates/langchain-ts/agent.ts`)

Python/CrewAI Agent (`templates/crewai-python/agent.py`)