@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

Start the server in HTTP mode:

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

In your n8n workflow, add an AI Agent node
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

cryptoapis-mcp-simulate