Micro-Frontend Architecture at Scale

When Your Frontend Becomes a Monolith

It starts innocently. A single Next.js app with a few pages. Then a few dozen. Then your bundle is 8MB, builds take 15 minutes, and three teams are stepping on each other's code.

Sound familiar?

The Monolith Frontend Problem

• Build times grow linearly with codebase size.
• Deployment risk — a CSS change in the checkout page breaks the dashboard.
• Team coupling — everyone works in the same repo, same CI/CD pipeline.

The Micro-Frontend Solution

Micro-frontends apply microservice principles to the frontend. Each team owns a vertical slice — from the UI layer down to its own API.

Our Approach at BWS

┌──────────────────────────────────────┐
│           App Shell (Host)           │
│  ┌──────────┐  ┌──────────────────┐  │
│  │  Header  │  │   Main Content   │  │
│  │  (shared)│  │  ┌────┐ ┌────┐  │  │
│  │          │  │  │ MF │ │ MF │  │  │
│  │          │  │  │ A  │ │ B  │  │  │
│  └──────────┘  │  └────┘ └────┘  │  │
│                └──────────────────┘  │
│  ┌──────────────────────────────────┐│
│  │          Footer (shared)         ││
│  └──────────────────────────────────┘│
└──────────────────────────────────────┘

Key Decisions

1. Module Federation — Webpack 5's Module Federation for runtime composition.
2. Shared Design System — A single npm package for UI primitives (buttons, cards, inputs).
3. Independent Deployments — Each micro-frontend deploys to its own CDN path.
4. Event Bus — Cross-module communication via custom events, not direct imports.

Trade-offs

Micro-frontends aren't free. They add complexity in:

• Routing — Who owns which URL?
• State sharing — Global auth state must be available everywhere.
• Consistency — Version drift in the shared design system.

But for organizations with 3+ teams working on distinct product areas, the autonomy gains far outweigh the costs.