paypack-langchain 0.1.8

One line of code. Three currencies. Alipay · WeChat Pay · USDC · ETH. Auto-routed by currency — one PayPackTool, three settlement networks. Featured use case: Zhihui Trading Terminal (production quant trading platform).

paypack-langchain

One line of code. Three currencies. Alipay · WeChat Pay · USDC · ETH.

pip install paypack-langchain

from paypack_langchain import PayPackTool

tool = PayPackTool(api_key="ppk_...", base_url="https://rhcjw.com/pay")
result = tool.run(amount=0.01, subject="AI data query")
# → Order created, ¥0.01, scan to pay

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Quick Start

Step 1: Get API Key

curl -X POST https://rhcjw.com/pay/v1/register \
  -H "Content-Type: application/json" \
  -d '{"name": "my_project"}'
# → {"api_key": "ppk_your_api_key"}

Step 2: Create a payment

from paypack_langchain import PayPackTool

tool = PayPackTool(
    api_key="ppk_your_api_key",
    base_url="https://rhcjw.com/pay"  # PayPack Cloud
)
result = tool.run(amount=0.01, subject="AI data query")
print(result)

Step 3: Check payment status

from paypack_langchain import PayPackQueryTool

query = PayPackQueryTool(
    api_key="ppk_your_api_key",
    base_url="https://rhcjw.com/pay"
)
print(query.run(order_id="PP2026071400ABC123"))
# → {"status": "success", "amount": 0.01}

---

Use with LangChain Agent

from langchain.agents import create_react_agent, AgentExecutor
from langchain_openai import ChatOpenAI
from langchain_core.tools import Tool
from paypack_langchain import PayPackTool

pay_tool = PayPackTool(
    api_key="ppk_your_api_key",
    base_url="https://rhcjw.com/pay"
)

tools = [
    Tool(
        name="pay_for_data",
        func=lambda q: pay_tool.run(amount=0.01, subject=q),
        description="Call when user needs paid data. Returns payment QR code."
    )
]

llm = ChatOpenAI(model="gpt-4")
agent = create_react_agent(
    llm, tools,
    prompt="You are a data assistant. For paid data, call pay_for_data first."
)
executor = AgentExecutor(agent=agent, tools=tools, verbose=True)

result = executor.invoke({"input": "Get latest market data"})
print(result)

---

Supported Currencies

Currency	Route	Networks	Example
CNY	PayPack Cloud	Alipay	currency="CNY"
CNY	PayPack Cloud	WeChat Pay	currency="CNY"
USDC	On-chain (local sign)	Base / Ethereum / Polygon / Arbitrum	currency="USDC", to="0x..."
ETH	On-chain (local sign)	Base / Ethereum / Polygon / Arbitrum	currency="ETH", to="0x..."

Auto-routed by currency parameter — one tool, three currencies.

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Featured Use Case: 志辉交易系统 (Zhihui Trading Terminal)

志辉交易系统 is a live quantitative trading platform that uses PayPack as its native payment layer:

• AI strategy agents autonomously pay for market data API calls
• Contest participants subscribe to backtesting engine time via WeChat/Alipay
• Risk management alerts trigger on-chain USDC settlements

This is not a toy demo — it's a production trading system processing real CNY and USDC payments every day.

👉 See it in action: https://rhcjw.com/pay

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API Reference

PayPackTool (Create Payment)

Param	Type	Required	Description
api_key	string	for CNY	API Key (ppk_...)
base_url	string	for CNY	https://rhcjw.com/pay
private_key	string	for USDC/ETH	Wallet private key or PRIVATE_KEY env var
network	string	optional	Default base-sepolia. Options: base-mainnet, base-sepolia, ethereum-mainnet, ethereum-sepolia, polygon-mainnet, arbitrum-mainnet
broadcast	bool	no	True = broadcast to chain, False = dry-run sign only
amount	float	yes	Amount (CNY in yuan, USDC/ETH in token units)
subject	string	yes	Description shown on payment page
currency	string	no	CNY (default) / USDC / ETH
to	string	for USDC/ETH	Recipient wallet address 0x...
callback_url	string	no	Webhook for payment result notification

PayPackQueryTool (Check Payment)

Param	Type	Required	Description
api_key	string	yes	API Key
base_url	string	yes	https://rhcjw.com/pay
order_id	string	yes	Order ID from PayPackTool response

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Links

• Live demo: https://rhcjw.com/pay
• GitHub: https://github.com/rhcjw/paypack
• Issues: https://github.com/rhcjw/paypack/issues

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Legacy users: the old langchain-paypack package is deprecated. Migrate to paypack-langchain for the latest features.