Working inside someone else's interface: ChurchBee
ChurchBee (https://bee.church) is a Chrome extension that makes newsletter building easier for churches. Instead of moving people into yet another dashboard, it puts a drag and drop editing experience inside the platform they already use. The price of that approach is dependency: when the host platform changes its own markup, the extension can break quietly. So you avoid binding to fragile selectors, keep every attachment point in one place in the codebase, and run a check that catches the breakage before a user reports it.
