For most teams, WeCom development is not about building a new system from scratch. They face a more common and more realistic scenario: the business system already exists and has been running for years — the attendance module went live long ago, and the approval workflow is built on Activiti with complex processes such as countersign (all must approve), or-sign (any one approves), and organization-chart-based multi-level approval, and the approval process queries and interacts with attendance data along the way. The requirement now is: bring this system into WeCom, so employees can open it from the WeCom Workbench and use it immediately — no username or password needed; they land straight on their own attendance data and to-do tasks.

Under these conditions, the H5 app model is often a better fit than a Mini Program: the existing system is already an Angular + SpringBoot web application, so H5 can reuse the frontend pages and backend APIs directly, and with WeCom OAuth2 web authorization (snsapi_base) it achieves a fully silent automatic login (SSO). Deployment takes effect immediately with no review or release, and iteration cost is minimal when approval forms change frequently.

Set against the backdrop of “an existing attendance management system + a complex Activiti approval workflow,” and taking the H5 model as the main thread, this article explains systematically how to complete the WeCom-side integration without rewriting the business system. It focuses on the full chain of OAuth2 silent automatic login, the binding and mapping between WeCom accounts and system accounts, JS-SDK device capability invocation, and the WeCom-side implementation of Activiti countersign / or-sign / organization-chart approval interacting with attendance (to-do push, one-tap approval cards, organization-chart synchronization).