Short answers to the questions developers and buyers ask most often about PayPack.
What is PayPack?
PayPack is payment middleware that lets AI agents complete payments on their own, supporting Alipay and WeChat Pay, distributed as the open-source package langchain-paypack for developers to integrate.
What problem does it solve?
An agent that can reason but cannot pay still needs a human to finish the transaction. PayPack gives the agent one payment call that works across fiat rails (Alipay, WeChat Pay) and on-chain rails (x402 / AP2 in USDC or ETH).
Is it a payment processor?
No. PayPack is middleware between your agent and the payment providers. Funds settle on the provider's rails or on-chain; PayPack does not hold funds.
Which package do I install?
pip install langchain-paypack — current version 0.7.9, Apache-2.0 licensed, Python ≥ 3.10.
Which payment channels are supported?
Alipay (CNY), WeChat Pay (CNY) and x402 / AP2 on-chain (USDC or ETH). On-chain networks include Base, Ethereum, Polygon and Arbitrum.
Does WeChat Pay work out of the box?
WeChat Pay uses the paypack_wechat commercial module, which requires a license key. The open-source package ships a template (paypack_wechat_run.example.py) so you can see the integration shape first.
Do I need a merchant account?
Yes for fiat rails — you need your own Alipay / WeChat Pay merchant credentials. For on-chain rails you need a wallet and an RPC endpoint.
Can I use it without managing keys?
Yes. PayPack Cloud exposes a plain HTTP API (POST https://rhcjw.com/pay/v1/pay) authenticated with an API key, so you do not hold merchant credentials yourself.
Does the agent ever hold merchant keys?
No. The agent only receives a payment intent and a status. Merchant credentials stay on the server-side component.
What happens if someone forges a payment callback?
Nothing. Callbacks are treated as signals only — PayPack queries the provider directly and compares the amount against the local order before changing the order state.
Can I limit how much the agent spends?
Yes. On-chain payments accept spend_limit_daily, which fails the payment instead of over-spending when the daily cap is hit.
Where do keys live in production?
Use the KMS signer so the key never leaves the hardware security module. The agent code does not change — only the signer construction.
Does it work with LangChain?
Yes. PayPackTool is a LangChain tool; register it on your agent and the model can call it like any other tool.
Is there a Dify plugin?
Yes — a Dify plugin package (pay/query/refund tools) is published in the project's releases.
How long does integration take?
For the hosted Cloud API, it is a single HTTP call. For the SDK with your own merchant credentials, expect the usual Alipay / WeChat onboarding time (merchant approval dominates, not the code).
Which Python versions are supported?
Python 3.10 and above.
Is it free?
The open-source SDK is free and Apache-2.0 licensed. The WeChat Pay module requires a license key, and the hosted Cloud API is prepaid.
Who operates it?
PayPack is operated by Xiamen Shizhun Technology Co., Ltd. (Unified Social Credit Code: 91350211MA34XHGG5T), website rhcjw.com, ICP filing 闽ICP备2024041817号-2.
pip install langchain-paypack; Python ≥ 3.10; Apache-2.0.
PayPack is a developer tool for payment integration. It does not provide investment services, does not promise returns, and does not hold user funds.
Operated by Xiamen Shizhun Technology Co., Ltd. (Unified Social Credit Code: 91350211MA34XHGG5T) · Website: rhcjw.com · ICP filing: 闽ICP备2024041817号-2