@cryptoapis-io/mcp-prepare-transactions

MCP server for Crypto APIs Prepare Transactions product. Build unsigned transactions for EVM, Tezos, Solana, Kaspa, XRP, UTXO, and Tron.

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

Features

• Prepare EVM native coin, ERC-20 fungible token, and ERC-721 NFT transfer transactions
• Prepare native Tezos (XTZ), FA1.2, and FA2 token transfer operations
• Prepare native SOL and SPL token transfer transactions on Solana
• Prepare native KAS transfers on Kaspa, with multi-recipient support
• Prepare native XRP transfers
• Prepare native coin transfers across 6 UTXO chains (Bitcoin, Bitcoin Cash, Litecoin, Dogecoin, Dash, Zcash)
• Prepare native TRX, TRC-20, and NFT transfers via Tron's dedicated prepare-transactions endpoints
• Returns unsigned transaction data ready for local signing

Prerequisites

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

Installation

npm install @cryptoapis-io/mcp-prepare-transactions

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

Usage

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

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

# HTTP transport (listens on 127.0.0.1; see "Exposing the server beyond localhost")
npx @cryptoapis-io/mcp-prepare-transactions --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-prepare-transactions": {
      "command": "npx",
      "args": ["-y", "@cryptoapis-io/mcp-prepare-transactions"],
      "env": {
        "CRYPTOAPIS_API_KEY": "your_api_key_here"
      }
    }
  }
}

Cursor

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

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

MCP Inspector

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

n8n

1. Start the server in HTTP mode:
   bash

   npx @cryptoapis-io/mcp-prepare-transactions --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

n8n in Docker: localhost inside the container is not your machine. Start the server with --host 0.0.0.0 and MCP_AUTH_TOKEN set (see Exposing the server beyond localhost), use http://host.docker.internal:3000/mcp as the URL, and add an Authorization: Bearer <token> header to the MCP Client Tool credential.

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

Available Tools

prepare_transactions_evm

Prepare unsigned EVM transactions.

prepare_transactions_tezos

Prepare unsigned Tezos operations (mainnet, shadownet).

prepare_transactions_solana

Prepare unsigned Solana transactions (mainnet, devnet).

prepare_transactions_kaspa

Prepare unsigned Kaspa transactions (mainnet only).

prepare_transactions_xrp

Prepare unsigned XRP transactions (mainnet, testnet).

prepare_transactions_utxo

Prepare unsigned UTXO transactions (Bitcoin, Bitcoin Cash, Litecoin, Dogecoin, Dash, Zcash; mainnet, testnet).

prepare_transactions_tron

Prepare unsigned Tron transactions via Tron's dedicated prepare-transactions endpoints (mainnet, nile).

CLI Arguments

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-prepare-transactions --transport http --port 3000
# Clients send x-api-key header with each request

Exposing the server beyond localhost

HTTP mode listens on 127.0.0.1 by default, so only processes on the same machine can reach it. To accept connections from other machines or containers, bind explicitly and protect the port:

# Startup-key mode: callers must present the token (the server refuses to start without one)
export MCP_AUTH_TOKEN=$(openssl rand -hex 32)
npx @cryptoapis-io/mcp-prepare-transactions --transport http --host 0.0.0.0 --port 3000 --api-key YOUR_API_KEY \
  --allowed-hosts mcp.internal.example
# Clients send: Authorization: Bearer $MCP_AUTH_TOKEN

# Per-request key mode: no startup key, every request must carry the caller's own x-api-key
npx @cryptoapis-io/mcp-prepare-transactions --transport http --host 0.0.0.0 --port 3000

--allowed-hosts restricts the Host header (DNS rebinding protection) when not bound to loopback. Prefer MCP_AUTH_TOKEN over --auth-token: command-line arguments are visible in the process list.

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