wechatpay-deduction-service

What problem does it solve?

This Skill helps developers implement WeChat Pay entrusted deduction (委托代扣) safely end to end by covering contract setup, deduction requests, notifications/callback handling, refunds, reconciliation, and troubleshooting for both merchant and partner service-provider modes.

Core Features & Use Cases

• Product selection & access mode alignment: Determine whether the business should use periodic deduction (24h delay or pre-notification) or “pay later” style (免密/先享后付), and choose the correct contract method by terminal type (public account H5, app, mini program, H5, or payment-in-contract for merchant mode).
• Integration knowledge base (V2/V3 protocol aware): Provide V2 (XML + APIv2 key) guidance for contract/deduction/termination/query/refund/billing/callback, with a strict exception that only the “pre-deduction notification” callback uses V3 (JSON + APIv3 key + RSA). Includes callback routing, idempotency, and concurrency handling rules.
• Official-doc-only reference + quality & issue resolution: Direct users to the correct interface index and reference materials, then apply a production-grade “go-live checklist” mindset and a dedicated problem troubleshooting manual for common errors (signature errors, V3 pre-notification verification failures, order closing/CONTRACT_NOT_EXIST, refund and reconciliation anomalies, etc.).

Quick Start

Ask the Skill to “help me choose the correct entrusted deduction mode and contract type for my scenario, then list the exact next integration steps and the required callbacks to implement.”