What is Microtoll?

Microtoll is a pay-per-use API gateway for AI agents. Instead of managing separate API keys and subscriptions for every service, your agent accesses paid APIs through a single MCP server — web search, transcription, image generation, LLMs, and more.

You only pay for what you use. No monthly subscriptions, no per-API signups. One wallet, all APIs.

Step 1: Set up your wallet

Microtoll payments use Spark — a Bitcoin layer that enables instant, near-zero-fee micropayments. Think of it like a prepaid balance: you load funds once, and your agent spends fractions of a cent per API call.

export SPARK_MNEMONIC="your 24 words here"

Alternative backends: LNbits (cloud Lightning wallet), NWC (Alby Hub), Phoenixd (self-hosted). Run microtoll setup to see all options.

Step 2: Install microtoll-mcp

pip install microtoll-mcp

Or use uvx (no install needed): uvx microtoll-mcp

Step 3: Configure MCP in LangChain

LangChain supports MCP tools via langchain-mcp-adapters.

Install the adapter and connect Microtoll as a tool provider.

from langchain_mcp_adapters.client import MultiServerMCPClient
from langgraph.prebuilt import create_react_agent
from langchain_openai import ChatOpenAI

async with MultiServerMCPClient({
    "microtoll": {
        "command": "uvx",
        "args": ["microtoll-mcp"],
        "env": {
            "SPARK_MNEMONIC": "your-24-word-mnemonic",
            "MICROTOLL_CONSUMER_TOKEN": "mct_...",  # optional, for Travel Rule services
        },
    }
}) as client:
    tools = client.get_tools()
    agent = create_react_agent(
        ChatOpenAI(model="gpt-4o"),
        tools,
    )
    result = await agent.ainvoke({
        "messages": "Search the web for AI agent payment solutions"
    })

Available tools

Once configured, your agent has access to these MCP tools:

Step 4: Verify it works

Ask your agent to search for something. It should: