How do I install X402engine?

Copy the stdio config for Cursor, Claude Desktop, Claude Code, or VS Code on this page. It uses the publisher's install, not a PlugMCP proxy.

Does X402engine need an API key?

The publisher lists these environment variables: X402_BASE_URL, X402_DEV_BYPASS, X402_PAYMENT_HEADER.

What transport does X402engine use?

X402engine runs locally over stdio.

When was X402engine last checked?

Last checked 2026-11-09. 50+ pay-per-call APIs for AI agents — images, LLM, code, crypto, travel & more via x402

X402engine MCP server

1{2 "mcpServers": {3 "io.github.agentc22-x402engine-mcp": {4 "command": "npx",5 "args": [6 "-y",7 "[email protected]"8 ],9 "env": {10 "X402_BASE_URL": "<value>",11 "X402_DEV_BYPASS": "<secret>",12 "X402_PAYMENT_HEADER": "<secret>"13 }14 }15 }16}

x402engine-mcp

Agent-friendly MCP server for x402engine. It lets agents discover and call pay-per-request APIs through HTTP 402, with automatic USDC payment on Base or Solana.

The live gateway covers LLMs, image and video generation, web search and scraping, code execution, crypto and wallet data, transaction simulation, audio, travel, and IPFS. This MCP exposes a curated tool set and live discovery for the full catalog.

Quick Start

Use a dedicated, low-balance payer wallet. The MCP signs x402 payments locally and never sends the private key to x402engine.

Base

{
  "mcpServers": {
    "x402engine": {
      "command": "npx",
      "args": ["-y", "[email protected]"],
      "env": {
        "X402_EVM_PRIVATE_KEY": "0xYOUR_DEDICATED_PAYER_KEY",
        "X402_PAYMENT_NETWORK": "base",
        "X402_MAX_PAYMENT_USD": "1.00"
      }
    }
  }
}

Fund the wallet with USDC on Base. The x402 facilitator pays transaction gas; the wallet signs an EIP-3009 USDC authorization.

Solana

{
  "mcpServers": {
    "x402engine": {
      "command": "npx",
      "args": ["-y", "[email protected]"],
      "env": {
        "X402_SOLANA_PRIVATE_KEY": "YOUR_BASE58_OR_JSON_PRIVATE_KEY",
        "X402_PAYMENT_NETWORK": "solana",
        "X402_MAX_PAYMENT_USD": "1.00"
      }
    }
  }
}

Fund the wallet with USDC on Solana and enough SOL for transaction fees.

Discovery Without a Wallet

The server starts without a wallet, and free tools such as discover_services and service_health still work. Paid tools return their x402 payment requirements until a wallet is configured.

claude mcp add x402engine -- npx -y [email protected]

Hermes Agent

Install the x402engine skill and merge this server into the active Hermes profile's config.yaml:

mcp_servers:
  x402engine:
    command: npx
    args: ["-y", "[email protected]"]
    env:
      X402_BASE_URL: "https://x402engine.app"
      X402_PAYMENT_NETWORK: "auto"
      X402_MAX_PAYMENT_USD: "0.10"

Start a new session and call discover_services or service_health; both are free. Keep the network on auto until a wallet is configured. For Base payments, store X402_EVM_PRIVATE_KEY in the profile's local .env, add X402_EVM_PRIVATE_KEY: "${X402_EVM_PRIVATE_KEY}" to the server's env, and change the network to base. Never put wallet keys in chat. The cap applies per request; authorize a separate total budget for each task.

Full Hermes setup guide · Installable skill

Payment Controls

Variable	Default	Description
`X402_EVM_PRIVATE_KEY`	unset	Dedicated payer key for Base USDC
`X402_SOLANA_PRIVATE_KEY`	unset	Base58 or JSON payer key for Solana USDC
`X402_PAYMENT_NETWORK`	`auto`	`auto`, `base`, or `solana`
`X402_MAX_PAYMENT_USD`	`1.00`	Hard per-request spending limit
`X402_BASE_URL`	production gateway	Override the gateway URL
`X402_PAYMENT_HEADER`	unset	Legacy pre-signed x402 header
`X402_DEV_BYPASS`	unset	Development bypass secret

In auto mode, Base is preferred when both keys are configured. Automatic payment only accepts the canonical USDC contracts on Base and Solana. It rejects unknown assets, unsupported networks, and amounts above the configured cap before signing.

MegaETH remains available to clients that supply their own compatible payment header.

MCP Tools

Category	Tools
Discovery	`discover_services`, `service_health`
Image and code	`generate_image`, `execute_code`
Audio	`transcribe_audio`
Crypto	`get_crypto_price`, `get_crypto_markets`, `get_crypto_history`, `get_trending_crypto`, `search_crypto`, `get_crypto_categories`
Wallet and token	`get_wallet_balances`, `get_wallet_transactions`, `get_wallet_pnl`, `get_token_prices`, `get_token_metadata`
IPFS	`pin_to_ipfs`, `get_from_ipfs`
Travel	`search_flights`, `search_locations`, `search_hotels`, `search_cheapest_dates`

Prices are included in each tool description and in live discovery. The gateway catalog can change independently of this package.

Discovery

Gateway discovery: /.well-known/x402.json
Agent card: /.well-known/agent.json
Endpoint manifest: /.well-known/agent-manifest.v1.json
Services API: /api/services
Package metadata: server.json

Development

npm install
npm test
npm run build

X402engine

Add this server

Host a copy with our keys and logs.

Server facts

Tools

Questions