Part 2: Patterns that Scale – Micro Frontends, BFF, and State Management

If Part 1: The Foundations of Front-end Architecture was about laying the foundations of front-end architecture, Part 2 is where the rubber really meets the road. Small apps can get away with simple folder structures, a handful of components, and context-based state. But as your SaaS product grows, complexity creeps in like an uninvited guest. Suddenly, what once worked fine starts breaking down under the weight of scale.

I’ve been there: 10 teams, hundreds of components, feature branches colliding, state leaking everywhere, and release cycles turning into a nightmare. The turning point for us was embracing scalable architecture patterns—namely Micro Frontends, Backends for Frontends (BFF), and robust state management strategies.

In this article, I’ll walk you through these patterns, why they matter, the trade-offs you need to know, and how to apply them in real-world SaaS projects.

Why Scaling Breaks Naive Architectures

At a small scale, your architecture can be pretty forgiving. A monolithic React app with a couple of routes and a single Redux store is manageable. But scaling introduces new pressures:

• More teams → more collisions. Without clear boundaries, two teams edit the same files, creating endless merge conflicts.
• More features → more state. Global state balloons, and suddenly a bug fix in user preferences breaks the checkout flow.
• More users → more performance needs. Loading everything in one bundle kills performance at scale.
• More platforms → more backend needs. Mobile, web, admin dashboards—each has different data requirements, but you’re stuck with a “one-size-fits-all” API.

This is where scalable patterns step in.

Micro Frontends: Breaking the Monolith

What Are Micro Frontends?

A micro frontend is to the UI what microservices are to the backend. Instead of one massive frontend codebase, you split your app into independently developed and deployed “slices.” Each team owns a slice—like billing, analytics, or onboarding—and stitches it into the app shell.

📊 Diagram: Micro Frontend Concept

[ App Shell ]
   ├── Billing (Team A)
   ├── Analytics (Team B)
   ├── Onboarding (Team C)

Why Use Micro Frontends?

1. Team Autonomy – Teams can develop, test, and deploy independently.
2. Technology Agnosticism – One team can use React, another Angular, another Vue.
3. Scalability – Codebases remain smaller and manageable.
4. Independent Deployments – No more waiting for the “big bang” release.

The Trade-offs

• Complexity in Setup – You need orchestration tools like Module Federation, Single-SPA, or import maps.
• Shared Concerns – Authentication, routing, theming, analytics must be standardized across slices.
• Performance Overhead – Loading multiple apps can hurt if not optimized (shared deps must be managed).

Example: Module Federation in Webpack

With Webpack 5 Module Federation, teams can share code at runtime:

Host (App Shell):

// webpack.config.js
plugins: [
  new ModuleFederationPlugin({
    name: "host",
    remotes: {
      billing: "billing@http://localhost:3001/remoteEntry.js",
    },
  }),
];

Remote (Billing App):

// webpack.config.js
plugins: [
  new ModuleFederationPlugin({
    name: "billing",
    filename: "remoteEntry.js",
    exposes: {
      "./BillingApp": "./src/App",
    },
  }),
];

Now the host app can load the billing frontend dynamically:

import BillingApp from "billing/BillingApp";

Real-world SaaS Scenario

In one project, we had a monolithic React app with 300+ components. Release cycles took weeks because everyone merged into one repo. After moving to micro frontends, each team had its own repo and deployment pipeline. Suddenly, the analytics team could ship updates without waiting on billing or onboarding. Release velocity doubled.

Backends for Frontends (BFF): Optimizing the Data Flow

The Problem

Most SaaS products serve multiple clients—web, mobile, admin dashboards, sometimes even IoT devices. If all clients hit the same backend API, you end up with:

• Over-fetching – Web gets way more data than needed.
• Under-fetching – Mobile needs more data and makes multiple round-trips.
• Bloated Frontend Logic – Frontend devs spend more time massaging API responses than building features.

Enter BFF (Backend for Frontend)

A BFF is a lightweight backend service that tailors data specifically for a given frontend.

📊 Diagram: BFF Flow

[ Backend Services ] 
     ↓
[ BFF Layer ] (web/mobile specific)
     ↓
[ Frontend App ]

Example: Node.js BFF

// server.js
const express = require("express");
const app = express();

app.get("/dashboard", async (req, res) => {
  const [profile, notifications] = await Promise.all([
    fetch(`http://backend/profile/${req.user.id}`).then(r => r.json()),
    fetch(`http://backend/notifications/${req.user.id}`).then(r => r.json()),
  ]);
  res.json({ profile, notifications });
});

app.listen(3000, () => console.log("BFF running on port 3000"));

Now the frontend just consumes /dashboard and gets exactly what it needs.

Benefits

• Cleaner frontend code (no stitching multiple APIs together)
• Performance boost (less over-fetching/under-fetching)
• Easier versioning (mobile and web can evolve independently)

Trade-offs

• Another service to maintain (adds DevOps overhead)
• Must sync contracts between BFF and frontend teams

Real-world SaaS Scenario

Our mobile app needed smaller payloads for low-bandwidth regions, while web could handle richer data. A BFF layer solved it: we delivered trimmed JSON for mobile and detailed analytics for web. Result: 40% faster mobile load times in APAC regions.

State Management in Front-end Web Development

If micro frontends and BFFs handle structure and data flow, state management handles consistency inside your app. And this is where I’ve seen teams succeed—or crash and burn.

The Golden Rule: Separate State Types

1. UI State – e.g., isModalOpen, currentTab, inputValue
2. Server State – e.g., user profile, orders list, notifications

Mixing these is where chaos begins.

Common Tools

• React Context → Great for small UI state
• Redux → Enterprise-level, predictable, but verbose
• Zustand / MobX → Lightweight global state alternatives
• React Query / Apollo → Perfect for server state (caching, retries, background refresh)

Example: React Query for Server State

import { useQuery } from "react-query";

function Profile() {
  const { data, error, isLoading } = useQuery("profile", () =>
    fetch("/api/profile").then(res => res.json())
  );

  if (isLoading) return <p>Loading...</p>;
  if (error) return <p>Error loading profile</p>;

  return <div>{data.name}</div>;
}

No manual loading states, caching, or retries. React Query handles it.

Real-world Scenario

One of our apps initially stored everything (including server data) in Redux. The store grew to thousands of lines, and a single bug in reducers caused cascading failures. Migrating server state to React Query cut boilerplate by 60% and reduced bugs drastically. Redux was then used purely for UI state like modals and feature toggles.

Case Study: Scaling a SaaS Dashboard

At one point, we had:

• 10 teams working across billing, analytics, onboarding, and admin
• A single backend API serving both web and mobile
• Redux everywhere, managing both UI and server state

The problems? Merge conflicts, bloated payloads, and unpredictable bugs.

Our solution:

• Split the frontend into micro frontends using Module Federation
• Introduced a BFF layer (Node.js) to tailor APIs for web vs mobile
• Migrated server state to React Query, kept UI state in Redux

The results?

• Independent deployments by each team
• 40% faster mobile load times
• 60% reduction in Redux boilerplate
• Happier developers (and fewer late-night firefights)

Frequently Asked Questions (FAQs)

Q: What are some software architecture patterns for front-end?

• Micro frontends
• Backends for frontends
• Component-driven architecture
• MVC (less common in modern SPAs, but still relevant in legacy apps)

Q: Should I use Redux in 2025?
Yes—but only if your app has complex UI state. For server state, prefer tools like React Query or Apollo.

Q: Is BFF overkill for small teams?
Yes. If you only serve one web frontend, a BFF might add unnecessary overhead. Introduce it when you support multiple platforms.

Final Thoughts

Scaling a frontend is like raising a kid. At first, you can get away with duct tape and quick hacks. But as they grow, you need structure, discipline, and systems that scale.

• Micro frontends give teams autonomy and scalability.
• BFFs optimize data flows and simplify frontend code.
• Modern state management keeps your UI predictable and maintainable.

The best frontend architecture isn’t about blindly adopting every pattern. It’s about recognizing when your current approach starts breaking—and knowing which pattern to bring in to fix it.

In Part 3, we’ll tie everything together and answer the big question: What really is the “best” front-end architecture? We’ll also talk about performance, developer experience, and the journey from developer to software architect.