In the rapidly evolving landscape of frontend development, we often find ourselves caught in a familiar cycle: rapid prototyping leads to tightly coupled code, which eventually becomes a maintenance nightmare. As applications grow in complexity and teams expand, the technical debt accumulated from mixing UI concerns with business logic becomes increasingly expensive to address.

Today, I want to share an architectural approach that has transformed how we build and maintain frontend applications — one that draws inspiration from domain-driven design and clean architecture principles to create a clear separation between UI components and domain logic.

The Problem with Traditional Frontend Architecture

Most frontend applications suffer from tight coupling between UI and business logic:

• Difficult testing: Business logic embedded within UI components is hard to isolate and test.
• Tight coupling with backend models: API request/response models are often intertwined with UI code, making backend changes ripple through the frontend.
• Framework lock-in → Want to add a mobile app or change the framework from React to Angular? Rewrite everything
• Scattered dependencies: Changes in backend services or data sources require widespread code modifications.
• Slow adaptability: Enterprise applications face frequent UI changes driven by product evolution, increasing backlog, and technical debt.
• Rigid data sources and library integrations: Switching data sources (e.g., GCP to S3) or third-party libraries can be cumbersome.

This creates maintenance nightmares and slows down development as teams grow.

Our Solution: Clean Architecture for Frontend

“UI framework dependencies should be kept separate from business logic”

Layer Breakdown:

• Domain Logic Layer: Encapsulates business rules, validation, and state management, independent of any UI framework.
• UI Layer: Composed of framework-agnostic components responsible solely for rendering and user interaction.
• Abstraction Layer: Acts as a mediator, exposing domain logic to the UI via well-defined interfaces or services.

Implementation Details

Workspace and Code Structuring

We organize the codebase using a monorepo with packages structured by business domains:

• Models Package: Shared domain models are maintained separately, synchronized with backend APIs to reflect changes automatically.
• Domain Modules: Business logic libraries encapsulated per domain.
• UI Components: Common UI components shared across ReactJS and React Native apps.
• Third-party Integrations: Authentication, storage, and analytics are integrated as pluggable services without impacting domain logic.

This pattern cleanly separates UI from domain logic, enabling independent evolution and testing.

Code Examples

Before: Tightly Coupled Architecture

import React , {
useState, useEffect }
from 'react' ;
const UserProfile = () => {
// State management in UI component
const [user, setUser] = useState ( null );
const [loading, setLoading] = useState ( false );
const [error, setError] = useState ( null ); // 🔴 Problem 1: API fetching in UI layer useEffect ( () => {
const fetchUser = async () => {
setLoading ( true );
try {
const response = await fetch ( '/api/user' );
const data = await response. json (); // 🔴 Problem 2: Business logic in UI (data. orders && data. orders . length > ) {
data. isPremium = data. orders . some ( order => order. total > 1000 && order. status === 'completed' ); }
setUser (data); }
catch (err) {
setError (err. message ); }
finally {
setLoading ( false ); } };
fetchUser (); }, []); // 🔴 Problem 3: Presentation mixed with logic
return ( <div> {loading && <p>Loading...</p>} {error && <p>Error: {error}</p>} {user && ( <div className={user.isPremium ? 'premium-badge' : ''}> <h2>{user.name}</h2> <p>Email: {user.email}</p> {/* More UI... */} </div> )} </div> ); };

After: Clean Architecture Implementation

// ------------------------------- // SERVICE LAYER (api/userService.ts) // ------------------------------- export
class UserService {
// ✅ Only data fetching concerns async fetchUser (): Promise < UserResponse > {
const response = await fetch ( '/api/user' );
return response. json (); } } // ------------------------------- // DOMAIN LAYER (domain/userDomain.ts) // ------------------------------- export
class UserDomain {
constructor ( private userService: UserService ) {} // ✅ Pure business logic async getUser (): Promise < User > {
const userData = await this . userService . fetchUser (); // Business rules encapsulated
return {
...userData, isPremium : this . checkPremiumStatus (userData) }; } // ✅ Testable without UI/API private checkPremiumStatus ( user : UserResponse ): boolean {
return user. orders ?. some ( order => order. total > 1000 && order. status === 'completed' ) || false ; } } // ------------------------------- // UI LAYER (components/UserProfile.tsx) // -------------------------------
import React , {
useState, useEffect }
from 'react' ;
import {
UserDomain }
from 'domain/userDomain' ;
import {
UserService }
from 'services/userService' ;
const UserProfile = () => {
const [user, setUser] = useState< User | null >( null );
const [loading, setLoading] = useState ( true );
useEffect ( () => {
// ✅ Clean composition
const userDomain = new UserDomain ( new UserService ());
userDomain. getUser () . then (setUser) .
finally ( () => setLoading ( false )); }, []); // ✅ Only presentation concerns
return ( <div> {loading ? <p>Loading...</p> : user && ( <div className={user.isPremium ? 'premium-badge' : ''}> <h2>{user.name}</h2> <p>Email: {user.email}</p> </div> )} </div> ); };

Key Benefits We’ve Seen

• Improved maintainability: Changes in UI or domain logic remain isolated, reducing regression risk.
• Enhanced testability: Business logic is independently testable without UI dependencies.
• UI framework flexibility: The UI layer can switch frameworks (e.g., React to React Native or Angular) without rewriting domain logic.
• Scalability: Modular design supports large enterprise applications with multiple teams.
• Metrics:
  - 40% reduction in UI-related bugs
  - 70% faster onboarding for new developers

Lessons Learned

Start Simple: Don’t over-abstract initially. Extract patterns as they emerge.

Performance Matters: The extra indirection can impact performance. Use memoization and code splitting strategically.

Team Adoption: Developers need time to adapt. Provide clear examples and gradual migration paths.

When to Use This Approach

This architecture works best for:

• Applications with complex business logic
• Teams planning multiple UI platforms (web + mobile)
• Long-term projects where maintainability matters
• Codebases with frequent UI changes

For simple CRUD apps or prototypes, it might be overkill.

Conclusion

• Recap the philosophy: “UI frameworks are delivery mechanisms, not architecture.”
• Call-to-action: “Try isolating one domain in your codebase — we bet you’ll never go back.”

Separating UI from business logic isn’t just good practice — it’s essential for building maintainable frontend applications at scale. While it requires initial setup, the long-term benefits in testability, maintainability, and flexibility make it worthwhile.

The key is treating your frontend like the complex application it is, not just a thin UI layer.

What’s your experience with frontend architecture patterns? Have you faced similar challenges? I’d love to hear your thoughts in the comments below.