io.github.CryptoAPIs-io/mcp-simulate

@cryptoapis-io/mcp-simulate

MCP server for Crypto APIs Simulate product. Dry-run EVM transactions to preview results without broadcasting.

API Version: Compatible with Crypto APIs version 2024-12-12

Features

• Simulate EVM transactions before broadcasting
• Preview transaction results, gas usage, and state changes
• Supports all EVM-compatible blockchains (Ethereum, Ethereum Classic, BSC, Polygon, Avalanche (C-Chain), Arbitrum, Base, Optimism, Tron)

Prerequisites

• Node.js 18+
• Crypto APIs account and API key (sign up | get API key)

Installation

npm install @cryptoapis-io/mcp-simulate

Or install all Crypto APIs MCP servers: npm install @cryptoapis-io/mcp

Usage

# Run with API key
npx @cryptoapis-io/mcp-simulate --api-key YOUR_API_KEY

# Or use environment variable
export CRYPTOAPIS_API_KEY=YOUR_API_KEY
npx @cryptoapis-io/mcp-simulate

# HTTP transport
npx @cryptoapis-io/mcp-simulate --transport http --port 3000 --api-key YOUR_API_KEY

Claude Desktop

Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json on macOS, %APPDATA%\Claude\claude_desktop_config.json on Windows):

{
  "mcpServers": {
    "cryptoapis-simulate": {
      "command": "npx",
      "args": ["-y", "@cryptoapis-io/mcp-simulate"],
      "env": {
        "CRYPTOAPIS_API_KEY": "your_api_key_here"
      }
    }
  }
}

Cursor

Add to .cursor/mcp.json (project) or ~/.cursor/mcp.json (global):

{
  "mcpServers": {
    "cryptoapis-simulate": {
      "command": "npx",
      "args": ["-y", "@cryptoapis-io/mcp-simulate"],
      "env": {
        "CRYPTOAPIS_API_KEY": "your_api_key_here"
      }
    }
  }
}

MCP Inspector

npx @modelcontextprotocol/inspector npx @cryptoapis-io/mcp-simulate --api-key YOUR_API_KEY

n8n

1. Start the server in HTTP mode:

   npx @cryptoapis-io/mcp-simulate --transport http --port 3000 --api-key YOUR_API_KEY
   

2. In your n8n workflow, add an AI Agent node
3. Under Tools, add an MCP Client Tool and set the URL to http://localhost:3000/mcp

All servers default to port 3000. Use --port to assign different ports when running multiple servers.

Available Tools

simulate_evm

Simulate an EVM transaction (dry run).

Parameter	Description
blockchain	Target blockchain (ethereum, binance-smart-chain, polygon, etc.)
network	Network (mainnet, sepolia, testnet, etc.)
fromAddress	Sender address
toAddress	Recipient address
value	Amount to send (in native coin)
data	Contract call data (hex)
gasLimit	Gas limit
gasPrice	Gas price

CLI Arguments

Argument	Description	Default
--api-key	Crypto APIs API key	CRYPTOAPIS_API_KEY env var
--transport	Transport type: stdio or http	stdio
--host	HTTP host	0.0.0.0
--port	HTTP port	3000
--path	HTTP path	/mcp
--stateless	Enable stateless HTTP mode	false

HTTP API Key Modes

When using HTTP transport, the server supports two API key modes:

• With --api-key: The key is used for all requests. x-api-key request headers are ignored.
• Without --api-key: Each request must include an x-api-key header with a valid Crypto APIs key. This enables hosting a public server where each user provides their own key.

# Per-request key mode (multi-tenant)
npx @cryptoapis-io/mcp-simulate --transport http --port 3000
# Clients send x-api-key header with each request

Stdio transport always requires an API key at startup.

Important: API Key Required

Warning: Making requests without a valid API key — or with an incorrect one — may result in your IP being banned from the Crypto APIs ecosystem. Always ensure a valid API key is configured before starting any server.

Remote MCP Server

Crypto APIs provides an official remote MCP server with all tools available via HTTP Streamable transport at https://ai.cryptoapis.io/mcp. Pass your API key via the x-api-key header — no installation required.

License

MIT