Onchain Data MCP

onchain-data-mcp

Give your AI assistant live blockchain data: wallet balances, payments, prices, scam checks and more. Free to start, no sign-ups needed.

The Claude Desktop button downloads a file you double-click; it has everything inside.

The Cursor and VS Code buttons only add the settings, so install the program first.

onchain-data-mcp is one small program that lets AI apps like Claude, Cursor and VS Code read the blockchain. It works with Ethereum, Base, Arbitrum, Optimism, Polygon, Avalanche, BNB Chain, Robinhood Chain and Solana.

Behind the scenes it asks about 30 data services ("providers") for you. If one is slow, busy or down, it quietly asks the next one. Free services come first, so you can start without paying anything and without any sign-ups.

A few words you will see here:

• MCP is a standard way for AI apps like Claude to use outside tools. This program is an "MCP server": a tool your AI app can use.
• API key is a free password a data provider gives you when you sign up. You don't need any to start. Adding a couple makes answers faster and more complete.
• Wallet address is the public "account number" of a crypto wallet, like 0xd8dA…6045 or 7xKX…9sHc.

Contents

• What you can do
• Quick start
• Connect to AI apps
• The dashboard
• Password and keys
• Data providers
• Available tools
• Real-world examples
• Running it for others
• Troubleshooting
• FAQ
• For developers · Security · License

What you can do

Ask your AI assistant questions in plain words. It picks the right tool and gets the answer.

• Check wallets. See what coins and tokens a wallet holds, on every chain at once. *"What does wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 hold?"*
• Confirm payments. Check that a customer really paid the right amount of USDC to the right address. *"Did transaction 0xabc… on Base pay 25 USDC to my shop address?"*
• Stay safe. Check if a token is a scam, if an address is on a sanctions list, or if a stablecoin is losing its value. *"Is this token on Solana a honeypot?"* · *"Is USDT still worth one dollar?"*
• Follow the money. Get transaction details, fees, and a bank-style statement for a wallet. *"Show me last week's incoming payments to my wallet, with their dollar value."*
• Prices and swaps. Get token prices from several sources, past prices, and swap quotes. *"What's the best price to swap 1 ETH to USDC on Arbitrum right now?"*
• Tokenized stocks. Look up stock tokens on Robinhood Chain and their prices. *"What is the price of the Tesla stock token on Robinhood Chain?"*

It only reads data, with one exception: it can send a transaction that you already signed yourself in your own wallet. It never holds your keys and can never move your money on its own.

Quick start

Three steps, about five minutes.

1. Install the program

Pick one. You only need to do this once.

Mac or Linux (open the Terminal app and paste):

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/madlabs-tech/onchain-data-mcp/releases/latest/download/onchain-data-mcp-installer.sh | sh

Windows (open PowerShell and paste):

powershell -ExecutionPolicy Bypass -c "irm https://github.com/madlabs-tech/onchain-data-mcp/releases/latest/download/onchain-data-mcp-installer.ps1 | iex"

Homebrew (Mac or Linux):

brew install madlabs-tech/tap/onchain-data-mcp

Claude Desktop only, no Terminal needed (Mac and Windows): download onchain-data-mcp.mcpb and double-click it. Claude Desktop asks for an optional dashboard password and optional provider keys. You can leave them all empty. Then skip to step 3.

Other ways: Docker, or build it yourself

Docker, for AI apps (Docker is a tool that runs programs in a sealed box):

docker run -i --rm -v onchain-data-mcp-data:/data ghcr.io/madlabs-tech/onchain-data-mcp:latest --config-dir /config

Docker, running in the background with the dashboard at http://127.0.0.1:8787/dashboard:

docker run -d --name onchain-data-mcp -p 127.0.0.1:8787:8787 -v onchain-data-mcp-data:/data -v onchain-data-mcp-config:/config ghcr.io/madlabs-tech/onchain-data-mcp:latest

docker exec onchain-data-mcp onchain-data-mcp password --config-dir /config

Build it yourself (needs Rust 1.90 or newer):

cargo build --release -p onchain-data-mcp

the program is now at target/release/onchain-data-mcp

When it's done, open a new Terminal window and check it works:

onchain-data-mcp --version

The installers put the program in a folder called .cargo/bin inside your home folder (for example /Users/you/.cargo/bin/onchain-data-mcp, or C:\Users\you\.cargo\bin\onchain-data-mcp.exe on Windows).

2. Connect your AI app

Follow the steps for your app in Connect to AI apps below. Then restart the app and ask it something, like *"Which chains can you read?"*

3. Open the dashboard

The dashboard is a control panel in your web browser. While your AI app is open, it runs at http://127.0.0.1:8787/dashboard. It is protected by a password that was made for you. To see it, run this in the Terminal (use the same folder you used in step 2):

onchain-data-mcp password --config-dir ~/.onchain-data-mcp

You'll see something like:

Dashboard: http://127.0.0.1:8787/dashboard

Password: f8460762fe006afc… One-click login: http://127.0.0.1:8787/dashboard#login=f8460762fe006afc… Config folder: /Users/you/.onchain-data-mcp Source: /Users/you/.onchain-data-mcp/dashboard_password

Open the one-click login link and you're in. The Setup guide walks you through the rest: add keys, pick tools, connect.

If you used the Claude Desktop bundle, your folder is ~/.onchain-data-mcp unless you picked another one.

Connect to AI apps

Pick one folder for your settings and use it everywhere. We use ~/.onchain-data-mcp here (a folder called .onchain-data-mcp in your home folder). Replace you with your user name.

Why the full path? Some apps start programs from a different place, so short paths like config end up in the wrong folder. A full path always works.

Claude Desktop

1. Open Claude Desktop, go to Settings → Developer → Edit Config. This opens claude_desktop_config.json:

• Mac: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

1. Paste this in (keep any other servers you already have inside "mcpServers"):

   {

"mcpServers": { "onchain-data": { "command": "/Users/you/.cargo/bin/onchain-data-mcp", "args": ["--config-dir", "/Users/you/.onchain-data-mcp"], "env": { "ODMSERVERDATA_DIR": "/Users/you/.onchain-data-mcp/data", "ALCHEMY_API_KEY": "", "HELIUS_API_KEY": "" } } } }

• command is where the program is. Find yours with which onchain-data-mcp (Mac/Linux) or where onchain-data-mcp (Windows). Homebrew puts it in /opt/homebrew/bin/onchain-data-mcp.
• On Windows, use paths like "C:\\Users\\you\\.cargo\\bin\\onchain-data-mcp.exe" (double backslashes).
• The keys are optional. Leave them empty, remove them, or add them later in the dashboard.

1. Quit Claude Desktop completely and open it again.

Claude Code

claude mcp add onchain-data -e ODM__SERVER__DATA_DIR=$HOME/.onchain-data-mcp/data -- onchain-data-mcp --config-dir $HOME/.onchain-data-mcp

Cursor

Click the Install in Cursor button at the top, or paste this into ~/.cursor/mcp.json (or .cursor/mcp.json inside one project), then turn it on in Cursor Settings → MCP:

{

"mcpServers": { "onchain-data": { "command": "/Users/you/.cargo/bin/onchain-data-mcp", "args": ["--config-dir", "/Users/you/.onchain-data-mcp"], "env": { "ODMSERVERDATA_DIR": "/Users/you/.onchain-data-mcp/data" } } } }

VS Code

Click the Install in VS Code button at the top. To use your settings folder, open the MCP settings in VS Code and add "args": ["--config-dir", "/Users/you/.onchain-data-mcp"].

Other apps (over the web address)

If the program is already running (for example started by another app, or with onchain-data-mcp serve), any app that supports MCP over HTTP can connect to:

http://127.0.0.1:8787/mcp

The dashboard's Connect page shows ready-to-copy settings with your real paths filled in.

The dashboard

Your control panel at http://127.0.0.1:8787/dashboard. Only your own computer can open it.

Password and keys

There are three kinds of keys. Only the first one is needed, and it is made for you.

| Provider keys | Your own free accounts at Alchemy, Helius and others. The program u