@cryptoapis-io/mcp-broadcast
MCP server for Crypto APIs Broadcast product. Submit locally signed transactions to the blockchain.
API Version: Compatible with Crypto APIs version 2024-12-12
Features
- Broadcast signed transaction hex to any supported blockchain
- Supports EVM (Ethereum, Ethereum Classic, BSC, Polygon, Avalanche (C-Chain), Arbitrum, Base, Optimism, Tron)
- Supports UTXO (Bitcoin, Bitcoin Cash, Litecoin, Dogecoin, Dash, Zcash)
- Works with transactions signed by
@cryptoapis-io/mcp-signeror any external signer
Prerequisites
- Node.js 18+
- Crypto APIs account and API key (sign up | get API key)
Installation
npm install @cryptoapis-io/mcp-broadcast
Or install all Crypto APIs MCP servers: npm install @cryptoapis-io/mcp
Usage
# Run with API key
npx @cryptoapis-io/mcp-broadcast --api-key YOUR_API_KEY
# Or use environment variable
export CRYPTOAPIS_API_KEY=YOUR_API_KEY
npx @cryptoapis-io/mcp-broadcast
# HTTP transport
npx @cryptoapis-io/mcp-broadcast --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-broadcast": {
"command": "npx",
"args": ["-y", "@cryptoapis-io/mcp-broadcast"],
"env": {
"CRYPTOAPIS_API_KEY": "your_api_key_here"
}
}
}
}
Cursor
Add to .cursor/mcp.json (project) or ~/.cursor/mcp.json (global):
{
"mcpServers": {
"cryptoapis-broadcast": {
"command": "npx",
"args": ["-y", "@cryptoapis-io/mcp-broadcast"],
"env": {
"CRYPTOAPIS_API_KEY": "your_api_key_here"
}
}
}
}
MCP Inspector
npx @modelcontextprotocol/inspector npx @cryptoapis-io/mcp-broadcast --api-key YOUR_API_KEY
n8n
- Start the server in HTTP mode:
npx @cryptoapis-io/mcp-broadcast --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
--portto assign different ports when running multiple servers.
Available Tools
broadcast_signed_transaction
Submit a signed transaction to the blockchain.
| Parameter | Description |
|---|---|
blockchain | Target blockchain (ethereum, bitcoin, binance-smart-chain, tron, polygon, etc.) |
network | Network (mainnet, testnet, sepolia, mordor, nile, amoy, fuji, etc.) |
signedTransactionHex | The signed transaction hex string to broadcast |
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-keyrequest headers are ignored. - Without
--api-key: Each request must include anx-api-keyheader 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-broadcast --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