Mempool MCP Server

An MCP server that connects AI assistants like Claude to mempool.space or your own self-hosted instance. Query blockchain data, mempool statistics, fees, mining pools, and Lightning Network information directly through natural language.

What is this?

This server acts as a bridge between AI assistants and Bitcoin blockchain data. Once configured, you can ask questions like:

• "What's the current Bitcoin block height?"
• "What are the recommended transaction fees right now?"
• "Show me the details of this transaction: [txid]"
• "What's the balance of address bc1q...?"
• "Which mining pools mined the most blocks this week?"
• "What's the current Lightning Network capacity?"

The server supports connecting to:

• Public API: mempool.space (default)
• Self-hosted: Your own Mempool instance
• Tor: .onion hidden services for privacy

Features

• 50+ tools covering all Mempool API endpoints
• Flexible connectivity: Public API, local instances, or Tor
• Auto Tor support: Automatically starts Tor when connecting to .onion addresses
• Custom SSL certificates: Support for self-signed certs on local instances

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Public API vs Self-Hosted

Why Self-Host?

The public mempool.space API has rate limits that may interrupt heavy usage. Running your own Mempool instance has no rate limits—query as fast and as often as you want.

Benefits of Self-Hosting

Running your own mempool instance eliminates these restrictions:

	Public API	Self-Hosted
Rate limits	Yes (shared with all users)	None
Query speed	Depends on server load	As fast as your hardware
Privacy	Queries visible to mempool.space	Fully private
Uptime	Depends on mempool.space	You control it
Data freshness	Real-time	Real-time (your own node)
Network support	None	Strengthens Bitcoin decentralization

Running a full Bitcoin node to power your Mempool instance also directly supports the network—every node helps validate and relay transactions, improving Bitcoin's decentralization and resilience.

Self-Hosted Options

• Mempool - Run the full stack yourself
• Start9 - One-click install on Start9 Embassy
• Umbrel - One-click install on Umbrel
• RaspiBlitz - Included in RaspiBlitz
• MyNode - Included in MyNode

Once you have a self-hosted instance, just point MEMPOOL_API_URL to it and enjoy unlimited queries.

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Requirements

Required

• Python 3.11+
• Claude Code or another MCP-compatible client

Optional (for Tor connectivity)

• Tor - Required only if connecting to .onion addresses

Installing Tor

Linux (Debian/Ubuntu):

sudo apt update && sudo apt install tor

Linux (Fedora):

sudo dnf install tor

Linux (Arch):

sudo pacman -S tor

macOS:

brew install tor

Windows:

There are two options for Tor on Windows:

Option A: Tor Expert Bundle (Recommended for MCP)

The Expert Bundle runs Tor as a background daemon on port 9050. This is what the MCP server expects by default.

1. Download from torproject.org/download/tor
2. Extract to C:\tor
3. Add C:\tor to your system PATH
4. Restart your terminal

Or use Chocolatey:

choco install tor

Option B: Tor Browser

If you already have Tor Browser installed, you can use it instead. Tor Browser runs on port 9150 (not 9050), so you need to configure the MCP server accordingly:

claude mcp add mempool-tor mempool-mcp --scope user --env MEMPOOL_API_URL=mempoolhqx4isw62xs7ldayuidyx2v2oethdhhj6mlo2r6ad.onion/api --env MEMPOOL_TOR_PROXY=socks5://127.0.0.1:9150 --env MEMPOOL_TOR_AUTO_START=false

Important: Tor Browser must be running when you use the MCP server with this configuration.

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Installation

Linux (Debian/Ubuntu):

sudo apt install pipx
pipx install mempool-mcp

Linux (other) / macOS:

pip install mempool-mcp
# Or use pipx if pip is blocked

Windows:

pip install mempool-mcp

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Configuration

Quick Start (Public API)

Linux/macOS:

claude mcp add mempool mempool-mcp --scope user --env MEMPOOL_API_URL=mempool.space/api

Windows (PowerShell):

claude mcp add mempool mempool-mcp --scope user --env MEMPOOL_API_URL=mempool.space/api

Note: On Windows, if mempool-mcp is not found, use the full path:

claude mcp add mempool "$env:APPDATA\Python\Python313\Scripts\mempool-mcp.exe" --scope user --env MEMPOOL_API_URL=mempool.space/api

Restart Claude Code, then ask: "What's the current Bitcoin block height?"

Manual Configuration

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

---

Option 1: Public API (mempool.space)

Use the public mempool.space API. No additional setup required.

{
  "mcpServers": {
    "mempool": {
      "type": "stdio",
      "command": "mempool-mcp",
      "env": {
        "MEMPOOL_API_URL": "mempool.space/api"
      }
    }
  }
}

---

Option 2: Self-Hosted Mempool Instance

Connect to your own Mempool instance running locally or on your network.

{
  "mcpServers": {
    "mempool": {
      "type": "stdio",
      "command": "mempool-mcp",
      "env": {
        "MEMPOOL_API_URL": "http://localhost:8999/api"
      }
    }
  }
}

With custom SSL certificate (e.g., Start9, Umbrel):

{
  "env": {
    "MEMPOOL_API_URL": "https://your-node.local/api",
    "MEMPOOL_CA_CERT": "/path/to/your-ca-certificate.crt"
  }
}

Disable SSL verification (not recommended for production):

{
  "env": {
    "MEMPOOL_API_URL": "https://your-node.local/api",
    "MEMPOOL_SSL_VERIFY": "false"
  }
}

---

Option 3: Tor Hidden Service (.onion)

Connect to Mempool via Tor for maximum privacy. The server will automatically start Tor if it's installed and not already running.

{
  "mcpServers": {
    "mempool": {
      "type": "stdio",
      "command": "mempool-mcp",
      "env": {
        "MEMPOOL_API_URL": "mempoolhqx4isw62xs7ldayuidyx2v2oethdhhj6mlo2r6ad.onion/api"
      }
    }
  }
}

With custom Tor proxy port:

{
  "env": {
    "MEMPOOL_API_URL": "mempoolhqx4isw62xs7ldayuidyx2v2oethdhhj6mlo2r6ad.onion/api",
    "MEMPOOL_TOR_PROXY": "socks5://127.0.0.1:9150"
  }
}

Disable Tor auto-start (use existing Tor instance):

{
  "env": {
    "MEMPOOL_TOR_AUTO_START": "false"
  }
}

---

Environment Variables

Variable	Default	Description
MEMPOOL_API_URL	(required)	Base URL for Mempool API
MEMPOOL_TOR_PROXY	socks5://127.0.0.1:9050	SOCKS5 proxy for .onion addresses
MEMPOOL_TOR_AUTO_START	true	Auto-start Tor if not running
MEMPOOL_CA_CERT	(none)	Path to CA certificate for self-signed SSL
MEMPOOL_SSL_VERIFY	true	Set to false to disable SSL verification

---

Available Tools

General (6 tools)

Tool	Description
get_server_info	Show current MCP server configuration
get_difficulty_adjustment	Current difficulty adjustment progress
get_recommended_fees	Recommended fee rates (sat/vB)
get_mempool_blocks	Projected mempool blocks with fee ranges
validate_address	Validate Bitcoin address and get type
get_historical_price	Historical Bitcoin price data

Mempool (5 tools)

Tool	Description
get_mempool	Mempool statistics (tx count, vsize, fees)
get_mempool_txids	All transaction IDs in mempool
get_mempool_recent	Recent mempool transactions
get_rbf_replacements	Recent RBF replacements
get_fullrbf_replacements	Full-RBF replacements

Transactions (8 tools)

Tool	Description
get_transaction	Full transaction details
get_transaction_hex	Raw transaction hex
get_transaction_status	Confirmation status
get_transaction_outspends	Output spending status
get_transaction_merkle_proof	Merkle inclusion proof
get_rbf_history	RBF replacement history
get_cpfp_info	CPFP fee information
push_transaction	Broadcast raw transaction

Blocks (9 tools)

Tool	Description
get_block	Block details by hash
get_block_by_height	Block hash by height
get_block_header	Raw block header hex
get_block_txids	Transaction IDs in block
get_block_txs	Block transactions (paginated)
get_blocks	Recent blocks
get_block_tip_height	Current block height
get_block_tip_hash	Current block hash
get_block_audit_summary	Block audit summary

Addresses (7 tools)

Tool	Description
get_address	Address info (balance, tx count)
get_address_txs	Address transaction history
get_address_txs_chain	Confirmed transactions (paginated)
get_address_txs_mempool	Unconfirmed transactions
get_address_utxos	Address UTXOs
get_scripthash	Scripthash info
get_scripthash_utxos	Scripthash UTXOs

Mining (11 tools)

Tool	Description
get_mining_pools	Pool statistics by interval
get_mining_pool	Specific pool info
get_mining_pool_hashrate	Pool hashrate history
get_mining_pool_blocks	Blocks mined by pool
get_hashrate	Network hashrate history
get_difficulty_adjustments	Difficulty adjustment history
get_reward_stats	Mining reward statistics
get_block_fees	Historical block fees
get_block_rewards	Historical block rewards
get_block_sizes	Historical block sizes/weights
get_block_fee_rates	Historical fee rates

Lightning Network (6 tools)

Tool	Description
get_lightning_statistics	Network statistics
get_lightning_nodes_rankings	Top nodes by capacity/channels/age
get_lightning_node	Node details by public key
search_lightning_nodes	Search nodes by alias
get_lightning_channels	Node channels
get_lightning_channel	Channel details

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Usage Examples

Once configured, ask your AI assistant:

Fees & Mempool:

• "What are the current recommended fees?"
• "How congested is the mempool right now?"
• "Show me the projected next blocks"

Transactions:

• "Look up transaction abc123..."
• "Is this transaction confirmed yet?"
• "What outputs from this tx have been spent?"

Addresses:

• "What's the balance of bc1q...?"
• "Show me the UTXOs for this address"
• "List recent transactions for this address"

Blocks:

• "What's the current block height?"
• "Show me details for block 800000"
• "Which transactions are in the latest block?"

Mining:

• "Which pools mined the most blocks this week?"
• "What's Foundry's current hashrate?"
• "Show me the network hashrate over the past month"

Lightning:

• "What's the total Lightning Network capacity?"
• "Find Lightning nodes with 'ACINQ' in the name"
• "Show me the top 10 nodes by capacity"

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Troubleshooting

"MEMPOOL_API_URL not set"

Make sure your MCP configuration includes the env section with MEMPOOL_API_URL.

MCP server not connecting / command not found (Windows)

After pip install mempool-mcp, the executable may not be in your PATH. Solutions:

Option 1: Use the full path in the MCP config:

claude mcp add mempool "$env:APPDATA\Python\Python313\Scripts\mempool-mcp.exe" --scope user --env MEMPOOL_API_URL=mempool.space/api

Option 2: Add Python Scripts to PATH:

[Environment]::SetEnvironmentVariable("Path", $env:Path + ";$env:APPDATA\Python\Python313\Scripts", "User")

Then restart your terminal.

Tor connection issues

"Tor is not installed" error:

• Linux/macOS: Install with your package manager (apt, dnf, pacman, brew)
• Windows: Install Tor Expert Bundle and add to PATH

Tor proxy connection failed:

1. Verify Tor is installed: which tor (Linux/macOS) or where tor (Windows)
2. Check the port:
   • Tor daemon/Expert Bundle uses port 9050 (default)
   • Tor Browser uses port 9150
3. Test connectivity:

   # Linux/macOS
   curl --socks5-hostname 127.0.0.1:9050 check.torproject.org
   
   # Windows PowerShell
   Test-NetConnection -ComputerName 127.0.0.1 -Port 9050

Using Tor Browser instead of Tor daemon:

Set these environment variables in your MCP config:

{
  "env": {
    "MEMPOOL_TOR_PROXY": "socks5://127.0.0.1:9150",
    "MEMPOOL_TOR_AUTO_START": "false"
  }
}

SSL certificate errors

For self-hosted instances with self-signed certificates:

• Set MEMPOOL_CA_CERT to your CA certificate path, OR
• Set MEMPOOL_SSL_VERIFY=false (not recommended for production)

Server not showing in Claude

1. Restart Claude Code after modifying ~/.claude.json
2. Make sure mempool-mcp is in your PATH (try running mempool-mcp --help)
3. Run /mcp in Claude to see server status

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License

MIT

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Links

• PyPI Package
• Mempool.space
• Mempool API Documentation
• MCP Protocol
• Claude Code