A custom element that fetched a canonical app's HTML and swapped document.body.innerHTML looked clean on the surface. It worked until it didn't: the swap raced with the existing app's event handlers, producing a tool that rendered correctly but did nothing. The correct pattern, an iframe pointing at the canonical URL with ?view=, was already in use by the VS Code extension. It took three weeks to apply the same answer to the web.
Ginexys
The Assumption That Seemed Reasonable
Ten SEO landing pages need unique <head> metadata but should load the same tool. A custom element that fetches the canonical tool HTML and injects it into the current page would deduplicate the tool code while keeping per-page metadata. One component, ten thin wrapper pages. Fewer moving parts.
How It Broke
