Micro-Frontends, One Year On: The Workarounds That Made Single-SPA Reliable for Us

A year ago, I wrote about our first year with micro-frontends . It was a frank retrospective: the win was framework autonomy and independent deploys, the cost was 20 GB of RAM during local dev, 15–20 minute deploy cycles, and a monorepo that became its own coordination tax. The closing line was the honest one — if I could choose again, I would think carefully about using Microfrontend or not. This article is the follow-up the previous one didn't write: what we actually built around Single-SPA to make it work. Not the architecture diagram. The workarounds. The dead code that's not really dead. The regexes we wish we didn't need. The .NET app no Single-SPA tutorial mentions. The browser-side singletons we use as message buses. The dev experience we documented and the parts we didn't. If you're evaluating Single-SPA in 2026, this is the article I wish I'd had a year ago. Where we left off The platform is a Single-SPA monorepo with seven in-repo apps and five shared packages. On top of that sit roughly ten standalone repositories for newer features, loaded at runtime via SystemJS import maps. Shared dependencies — React 18.2, ReactDOM, axios, react-bootstrap, single-spa 5.9.5 — are served from CDN and externalized in every webpack config. The architecture is textbook. The reality, a year in, is that the textbook stops where the workarounds start. The shell isn't where you think it is If you read our frontend repo you'd conclude the shell is whatever directory has single-spa in its package.json . That's where Single-SPA gets configured. That's where start() is called. There's even a webpack entry that, until recently, was producing an index.ejs HTML template. That HTML template is dead code. The real shell — the HTML the browser actually receives, in every environment — is rendered by an ASP.NET MVC application, in a Razor view. The frontend repo ships JavaScript modules. The .NET host ships the page that loads them. That's the unlock. Once you see this, every other work