x402engine

official

50+ pay-per-call APIs for AI agents via HTTP 402 crypto micropayments. $0.001–$0.12 per call with USDC and USDm.

What can you do with x402engine MCP?

Discover paid APIs — Ask your assistant to list available pay-per-request services via discover_services and check their status with service_health.
Generate images and run code — Request image creation with generate_image or code execution with execute_code, with automatic USDC payment on Base or Solana.
Query crypto and wallet data — Get prices, market trends, wallet balances, transactions, and token metadata using tools like get_crypto_price and get_wallet_balances.
Process audio and IPFS — Transcribe audio files with transcribe_audio, or pin and retrieve content from IPFS using pin_to_ipfs and get_from_ipfs.
Search travel options — Find flights, hotels, locations, and cheapest travel dates with tools like search_flights and search_hotels.

Documentation

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", "x402engine-mcp@1.1.1"],
      "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", "x402engine-mcp@1.1.1"],
      "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 x402engine-mcp@1.1.1

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", "x402engine-mcp@1.1.1"]
    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