When I joined Ionic Wealth as the first engineering hire, we had a single React app doing everything. Eighteen months later, we had decomposed it into independently deployable modules. Here's what that journey actually looked like.
Why we moved
The monolith wasn't broken it was fast to start with. But as the product grew across CRM, client-facing flows, and admin tooling, every deploy became a coordinated event. A bug fix in one module required a full regression pass on three others.
The trigger was onboarding. KYC is compliance-critical and high-churn we were iterating on it weekly. Coupling it to the rest of the app made fast iteration expensive and risky.
The approach
We didn't rewrite. We extracted. Starting with the highest-change-frequency module (onboarding), we wrapped it behind a well-defined contract: shared auth state, a design token system, and a routing protocol.
Module Federation (Webpack 5) handled runtime composition. Each module had its own CI pipeline and could be deployed independently.
What no one talks about
Shared state is the hard part. Routing and auth felt solved. Shared component state across modules especially things like notification banners, global modals, and user session data required deliberate architecture. We ended up with a lightweight event bus.
Build caches get complicated. Each module has its own node_modules. Dependency drift between modules caused subtle runtime errors that were hard to debug. Lockfile discipline and shared dependency manifests became mandatory.
The DX tax is real. Local development with three simultaneous dev servers and hot module replacement across module boundaries is not seamless. We invested in a developer proxy that unified the experience, but it took time.
Was it worth it?
For us, yes. We went from full-team coordination on every deploy to teams shipping their modules independently, same week. Onboarding iteration velocity roughly doubled.
The architecture is right when the pain of coordination exceeds the pain of distribution. For a founding-stage team with one module changing constantly, that threshold arrived earlier than I expected.