A guide to modern frontend architecture patterns

Frontend architecture patterns are reusable guidelines that structure any one software product’s implementation on… you guessed it, the frontend. Modern software development teams use a variety of frontend architecture patterns (monolithic, modular, and component-based, just to name a few). The choice of which pattern to use depends on project complexity, scalability, maintainability, product delivery concerns, and development preferences.

Your frontend architecture is the foundation of the frontend codebase you’ll maintain during the product’s lifetime, so choosing the optimal frontend architecture is a must.

In this article, we’ll discuss all popular frontend architecture patterns, their strengths, weaknesses, and usage examples. Use this article as a guide to select the optimal frontend architecture for your next sustainable software product!

Why should you select the optimal frontend architecture?

We can theoretically build any software product using any available frontend architecture pattern. That’s because an architecture pattern offers a general, reusable way to structure a UI implementation — not a strict, specific development ruleset.

However, it should be noted during practical frontend development, that not all architectural patterns offer the same developer productivity. These patterns help us achieve development goals by satisfying business requirements.

So, we should always select the optimal architecture based on project complexity, scalability, maintainability, product delivery concerns (cost and time), and developer preferences.

Choosing the optimal frontend architecture will:

• Create high-quality, sustainable, high-performance software products
• Improve the codebase health, quality, maintainability, and increase product lifetime
• Boost developer productivity and attract new developers
• Optimize development costs

Popular frontend architecture patterns

In this article, we’ll discuss the following popular, modern architecture patterns that you can use to build web, mobile, or desktop software products:

• Monolithic architecture
• Modular architecture
• Component-based architecture
• Microfrontend architecture
• Flux architecture
• Hybrid/mixed architecture

Let’s explore each architecture:

Monolithic architecture

Monolithic architecture hosts the entire app frontend’s interfaces, resources, and dependency module sources in just one project codebase. Monolithic app codebases typically use MVC (model-view-controller) alongside components, widgets, layout fragments, and other UI code decomposition strategies to organize code. The point being — all UI source files are stored within the monolithic code repository.

Strengths of monolithic architecture

• Offers the simplest complete codebase structure for small projects
• Beginner-friendly development environment since every codebase component is stored in one code repository
• Simplifies debugging and testing since a monolithic project has no separate dependency projects
• Simplifies the deployment process and pre-deployment workflows
• Organizations can expect fast initial project handover and reduced development costs from initial development cycles
• Doesn’t require sub-project integration tools or deployment sync since there is only one project usually maintained with one IDE (integrated development environment)

Weaknesses of monolithic architecture

• Codebase complexity grows with the project size and affects maintainability and developer-productivity
• Comes with scalability limitations since the whole project source is a tightly coupled codebase
• Can create collaboration limitations and problematic code integration scenarios during development, i.e., frequent merge conflicts
• Deployment completions typically take more time and restart the entire app

Use cases

Monolithic frontend architecture suits simpler software frontends maintained by small to medium-sized software development teams. This pattern works best in scenarios where developers prioritize faster initial project delivery over scalability and future codebase growth prevention.

For example, a small software team might choose the monolithic frontend pattern to build the frontend of a medium-sized enterprise app.

Example projects

Most open source SPAs (single-page applications), multi-page web apps, and other frontend projects hosted on a single GitHub code repository typically use monolithic architecture with component-based, MVC, or traditional page-based codebase arrangement. For example, this to–do app source code uses a monolithic frontend with the MVC pattern:

Modular architecture

Modular architecture decomposes the codebase into separate, maintainable, and installable modules. Developers split the primary app code into sub-modules based on functionality, so they can develop, test, and deploy them as isolated entities without creating collaborative development conflicts.

The modular pattern turns a single monolithic code repository into separately maintained code repositories, but the resulting software UI is still considered a monolith. This is because modules get integrated to construct the final app.

Strengths of modular architecture

• Reduces the main codebase complexity and improves maintainability factors since code gets divided into separate submodule projects
• Improves collaboration through parallel development and reduces collaborative development conflicts
• Allows developers to adhere to the generic plugin-core architecture pattern for better code arrangement
• Distributes test and deployment scripts into modules, reducing the primary codebase complexity
• Offers better unit test arrangement since tests can be distributed among modules

Weaknesses of modular architecture

• Primary codebase complexity grows when the submodule count increases
• Beginners should become familiar with modules, module integration, and SCM (source code management) submodules (i.e., Git submodules) before starting with development
• Difficult to see a whole project codebase snapshot from one code repository
• Deployments are typically slow and restart the entire app

Use cases

The modular pattern is a strategy to improve the maintainability and collaboration factors of large monolithic codebases without going through expensive rewrites. Developers who can invest the initial development time for future collaboration and maintainability benefits choose the modular architecture.

For example, a medium-sized software team might choose modular architecture for a medium-scale ecommerce app to create and maintain shopping, checkout, product management, and financial modules.

Example projects

Web developers use Lerna-like monorepo management tools to implement productive modular frontends. This sample Lerna project guides how to implement the modular architecture pattern for a simple web app.

Component-based architecture

The component-based architecture recommends using reusable components to construct the software product interface. Components host a template, UI logic, and styles and developers usually divide large UIs into components based on functionality and relevance. A component-based app renders a screen by constructing a component tree and passes messages between components to implement interactivity. The component-based architecture is the fundamental concept in popular frontend libraries like React, Vue, Angular, and Svelte.

Strengths of component-based architecture

• Improves maintainability, readability, and developer productivity by constructing the render-tree-like structure within the codebase
• Easy to decompose the whole app layout into atomic elements based on functionality and relevance
• Aggregates template, logic, and styles into one atomic segment promoting better code structure and isolation
• Keeps UI/UX consistent while also allowing code-to-design UI workflow implementation through reusable components

Weaknesses of component-based architecture

• Difficult to handle the application state with large component trees, possibly requiring additional library features to solve state management issues (i.e., the React Context API) to reduce the component tree source’s data flow complexity
• Component-based unit tests are simple and self-explanatory, but developers have to spend time implementing mock services to implement them
• Beginners have to master component-based architecture, best practices, and design patterns (i.e., React Hooks) before applying

Use cases

The component-based architecture is the foundation of popular frontend libraries, so developers must adhere to it to develop software UIs per those libraries. Developers who strive for code reusability, render-tree-like code structure, and component-based unit tests choose the component-based architecture.

For example, a mobile app developer might use component-based architecture with the React Native framework to build a social media app.

Example projects

Every modern frontend library recommends that developers build apps using component-based architecture. Browse any React, Angular, Vue, and Svelte apps to check the component-based architecture pattern. For example, this simple React Native chat app source uses the component-based architecture:

Microfrontend architecture

The microfrontend architecture motivates developers to divide the app frontend into isolated, maintainable frontend projects, known as microfrontends. Developers can create microfrontends with UI segments, components, modules, or even entire app frontends based on the complexity of the product and development preferences.

A software system that follows the microfrontend pattern has two types of separate projects:

• The host app: Responsible for loading microfrontends and managing microfrontend execution life cycles
• Microfrontends: Provide functionality to the host app on demand

Strengths of microfrontend architecture

• Improved scalability and maintainability factors due to the creation of reusable microfrontends
• Loads frontend segments on demand through the network usually via different web servers, so microfrontend pattern offers great performance and optimal resource usage benefits
• Easy to assign frontend segment projects to teams based on domain divisions or functionality
• Silent deployments without even restarting the host app

Weaknesses of microfrontend architecture

• Using microfrontends usually complicates the entire product architecture, deployment workflows, development practices
• Slows down the initial product development and feature deliveries because of the microfrontend architecture-related setup and configuration
• Understanding the microfrontend architecture can be challenging for some frontend developers
• Standardization is required to preserve UI/UX consistency since microfrontends are isolated projects

Use cases

Microfrontend architecture provides solutions for maintainability, scalability, and deployment issues for complex and large-scale monolithic frontend projects. Microfrontend architecture also brings impressive code reusability benefits when it comes to separate app frontend instances.

Microfrontend architecture is the recommended approach for complex projects maintained by large development teams. In a real-life application, a company might build a complete ERP (enterprise resource planning) app by creating microfrontends for different ERP submodules.

Example projects

The open source community doesn’t have many fully-featured, complete, and up-to-date microfrontend projects available to see, seeing as the microfrontend architecture is often used in closed-source, large enterprise systems, but you can browse this GitHub repository to see a simple microfrontend app built with React:

Flux architecture

Meta (formerly Facebook) introduced the Flux architecture for developing client-side web applications. The Flux architecture pattern introduces a better solution for application state and data flow in complex component-based apps. Flux simplifies the decentralized, bidirectional, complex nature of the application state and data flow by creating centralized state stores and introducing a unidirectional data flow. Flux introduces three fundamental elements for constructing the app frontend:

• Dispatcher: Dispatches actions (i.e., add a new todo item) to the store to update the centralized state
• Store: Holds the application state as an immutable object and logic. Notifies views when the state gets updated
• View: Presentable UI of the app, usually components. Dispatches actions through dispatchers

Redux-like state management libraries use a simplified version of the Flux architecture. Redux uses Flux without multiple stores and uses the reducers concept within the store element.

Strengths of Flux architecture

• Reduces state management and data flow complexity in component-based apps
• Improves maintainability and developer-productivity factors via a predictable state and clear code division
• Helps developers understand app behavior and UI updates without inspecting components, since Flux aggregates logic into stores (reducers in Redux)
• Easily implements replayable application state and easy-to-handle app logging features
• Offers a simple, productive debugging experience since all app state-bound actions go through stores

Weaknesses of Flux architecture

• Doesn’t offer productive development experience for developers who aren’t familiar with the Flux concept
• Moves the component logic away from the component itself to stores, meaning Flux can complicate simple projects
• Introduces more boilerplate code to set up the Flux architecture within the frontend codebase
• Increased overall codebase’s engineering complexity since Flux adds another abstraction layer for app logic with several code elements

Use cases

Flux offers a different concept for handling application state and controlling data flow by competing with existing MVC-like patterns. Though Flux adds another abstraction layer for your app logic and introduces more boilerplate code, it impressively reduces state handling and data flow complexity in component-based apps. All in all, the Flux architecture is suitable for medium-sized or large component-based apps with complex, frequently updated states.

Developers might use Flux (via Redux or similar libraries) to develop a component-based frontend for a fully-featured live chat app or social media app.

Example projects

The examples directory in the official Flux architecture documentation repository contains multiple examples of Flux in action. On the other hand, the Meta team recommends using Redux-like libraries that use a simplified implementation of the Flux architecture. See this sample to-do app source to understand the Flux architecture from Redux API usage:

Hybrid/mixed architecture

The frontend architecture patterns we’ve discussed so far recommend a specific way to structure the app codebase to meet developer requirements and satisfy the organization’s goals. These patterns will affect codebase structure and arrangement, but they don’t restrict you from using other architecture.

Most developers use hybrid or mixed architecture patterns, adhering to multiple architecture patterns. Here are some examples:

• Using both monolithic and component-based hybrid architecture to develop a website
• Using modular, component-based, and Flux architecture to develop a medium-sized ecommerce app
• Using a component-based pattern and the Flux app in a microfrontend host app that serves a complex enterprise software system

Following strictly only a single frontend architecture pattern isn’t mandatory, so consider using multiple architectures based on your development preferences and organizational goals.

Comparison of frontend architecture patterns

The following table summarizes key points and shows when to consider using each frontend architecture pattern:

Comparison factor	Monolithic	Modular	Component-based	Microfrontend	Flux
Key development approach	Hosts every frontend source file within a single repository	Separates fronted source code into modules	Divides the frontend code into reusable components	Divides the frontend code into isolated apps or fully-featured components and loads them on-demand	Separates frontend source code into views, dispatchers, and stores
Usage in simple projects	Recommended	Not recommended (Increases complexity)	Recommended	Not recommended (Increases complexity)	Not recommended (Increases complexity)
Usage in medium projects	Partially recommended (Maintainable, but increases complexity)	Recommended	Recommended	Partially recommended (Maintainable, but increases complexity)	Recommended if developers prefer to use
Usage in large projects	Not recommended (increases complexity)	Partially recommended (Maintainable, but increases complexity)	Recommended	Recommended	Recommended if developers prefer to use
Beginner-friendly?	Yes	Perhaps	Yes	No	No
Initial product releases and demos	Fast since the architecture is simple	Fast but not so fast compared to monolithic due to initial setup	Fast since the architecture is simple	Slow due to complicated initial setup	Fast but not so fast compared to pure component-based architecture due to initial boilerplate code and setup

Conclusion

In this article, we’ve explored popular frontend architecture patterns by discussing key points, strengths, weaknesses, usage scenarios, and example projects. We also went through a table that helps you choose the optimal architecture based on various development and organizational factors.

The architecture we decide to use will establish a foundation for your entire frontend source code. So, we should always select the optimal architecture to prevent expensive rewrites and refactorings in the future. There is no strict rule telling you to follow just one architecture pattern  —  you can adhere to multiple patterns and structure your frontend codebase based on your preferences and business requirements.

Monolithic, modular, component-based, microfrontend, and Flux are the popular frontend architecture patterns that most software development teams use. Keep in mind that there’s still room for you to innovate your own architecture pattern by examining your frontend development requirements, just like how Meta developers came up with Flux.