MoltyDEX LangChain Integration

Add x402 payment handling to your LangChain agents with this easy-to-use integration.

What is MoltyDEX?

MoltyDEX is a DEX aggregator built specifically for x402 payments. It automatically swaps tokens when agents receive 402 Payment Required responses, making x402 adoption seamless.

Installation

pip install langchain moltydex

Quick Start

from langchain.agents import AgentExecutor, create_openai_functions_agent
from langchain_openai import ChatOpenAI
from moltydex.langchain import MoltyDEXTool, X402PaymentMiddleware

# Initialize MoltyDEX tool
moltydex_tool = MoltyDEXTool(wallet_path="wallet.json")

# Add x402 payment middleware
middleware = X402PaymentMiddleware(moltydex_tool)

# Create agent with x402 support
llm = ChatOpenAI(model="gpt-4")
tools = [moltydex_tool]
agent = create_openai_functions_agent(llm, tools, prompt)
agent_executor = AgentExecutor(agent=agent, tools=tools, middleware=[middleware])

# Your agent now automatically handles 402 payments!
result = agent_executor.invoke({"input": "Get data from https://api.example.com/data"})

Features

✅ Automatic 402 Handling - Automatically swaps tokens when needed
✅ Balance Checking - Checks token balances before payment
✅ LangChain Native - Works seamlessly with LangChain agents
✅ Tool Integration - Expose MoltyDEX as a LangChain tool
✅ Middleware Support - Intercept and handle 402 responses

How It Works

1. Agent makes request - Your LangChain agent makes a request to an x402-protected API
2. 402 detected - Middleware detects 402 Payment Required response
3. Auto swap - MoltyDEX automatically swaps tokens if needed
4. Payment made - Payment is made automatically
5. Request retried - Original request is retried with payment proof

Example: Complete Agent

from langchain.agents import AgentExecutor, create_openai_functions_agent
from langchain_openai import ChatOpenAI
from langchain.tools import Tool
from moltydex.langchain import MoltyDEXTool, X402PaymentMiddleware
import requests

# Initialize MoltyDEX
moltydex = MoltyDEXTool(wallet_path="wallet.json")

# Create custom tool for API calls
def call_api(url: str) -> str:
    """Call an API endpoint"""
    response = requests.get(url)
    if response.status_code == 402:
        # Middleware will handle this automatically
        return "Payment required - handling automatically..."
    return response.text

api_tool = Tool(
    name="call_api",
    func=call_api,
    description="Call an API endpoint"
)

# Create agent
llm = ChatOpenAI(model="gpt-4")
tools = [moltydex, api_tool]
agent = create_openai_functions_agent(llm, tools, prompt)
agent_executor = AgentExecutor(
    agent=agent, 
    tools=tools, 
    middleware=[X402PaymentMiddleware(moltydex)]
)

# Use agent
result = agent_executor.invoke({
    "input": "Get data from https://api.example.com/data"
})

API Reference

MoltyDEXTool

LangChain tool wrapper for MoltyDEX operations.

from moltydex.langchain import MoltyDEXTool

tool = MoltyDEXTool(wallet_path="wallet.json")

X402PaymentMiddleware

Middleware that automatically handles 402 responses.

from moltydex.langchain import X402PaymentMiddleware

middleware = X402PaymentMiddleware(moltydex_tool)

Resources

• MoltyDEX Website: https://www.moltydex.com
• MoltyDEX Docs: https://www.moltydex.com/developers
• x402 Example: https://github.com/Djtrixuk/moltydex-x402-example
• LangChain Docs: https://python.langchain.com

License

MIT

Contributing

Contributions welcome! Open an issue or submit a PR.

Built with ❤️ for the LangChain and x402 communities