Why Module Federation — Building an Enterprise MFE Platform (Part 1)

This series walks through an actual enterprise microfrontend platform, end to end: one Host shell, three shared platform microfrontends, a manifest-driven mechanism for mounting any number of independently-owned domain microfrontends, a full OIDC auth flow, and a CI/CD pipeline. Every code snippet in this series is real and traceable to the actual boilerplate it's built from, on GitHub . Part 1 is the decision everything else in this series depends on: why Module Federation , and not one of the two other credible options. The one requirement that rules everything else out Strip away the buzzwords, and an "enterprise microfrontend platform" only has to guarantee one thing: a team ships a change to their part of the app without anyone else redeploying anything. Not "in theory, with enough coordination" — actually, mechanically, true. If shipping one team's bug fix requires a platform team to cut a release, this isn't microfrontends — it's a monolith with extra steps. That single requirement rules out more than it looks like it should. It rules out compiling every team's code into one shared build (that's just a single-page app with more steps). And it rules out anything where the Host app needs to know, at its own build time, which teams' pages exist and which version of each — because "known when the Host was built" and "deployed independently of the Host" are opposites. The decision Use Webpack 5 Module Federation , in runtime-composition mode, as the platform's way of putting every team's page together into one app: The Host ships with an empty list of remote apps built in. Instead, it looks up every team's page from a small list — a manifest — that it fetches fresh every time the app loads. React, the shared state layer, and the shared design system are all declared as singletons : every team's page gets the exact same running instance of each, not its own separate copy. "Deploying" a team's page means adding or updating one entry in that manifest. The Host itself