Microfrontend : Best practices and design patterns — Part 2

7 min readMay 10, 2023

In the first part of our microfrontend architecture series, we dug into the fundamentals, benefits, challenges, and real-world use cases of this cutting-edge methodology for developing web application development. We learned that microfrontends enable better separation of concerns, greater scalability, and improved team autonomy by breaking down large, monolithic applications into smaller and more manageable components.

As we move into the second part of this series, we will explore best practices for designing and developing microfrontends. We’ll try to have a look on the importance of establishing clear boundaries, implementing a shared design system, optimizing performance, streamlining cross-component communication, and developing robust testing strategies, among other key topics.

Moreover, we will also examine various design patterns that can help you build a scalable, maintainable, and efficient microfrontend architecture. These patterns will address essential aspects such as composition, event-based communication, server-side composition, and cross-cutting concerns.

So let’s dive into the exciting world of microfrontends and discover how they can revolutionize the way you approach web development!

Best Practices

As the popularity of microfrontend architecture continues to grow, it becomes increasingly essential to understand and implement best practices that can help ensure the success of your web applications. By following these best practices, you can harness the full potential of microfrontends, while minimizing potential pitfalls and complexities.

By adhering to these best practices, you will be better equipped to tackle the challenges associated with microfrontend architecture and create scalable, flexible, and maintainable web applications. So, let’s discover the best practices that can make a difference in your microfrontend projects!

1. Establish Clear Boundaries and Responsibilities

To ensure a successful microfrontend implementation, you need to define a clear boundaries and responsibilities for each component. For example, imagine an e-commerce platform with separate microfrontends for the product catalog(ReactJS), shopping cart(Angular), and user account management(ReactJS). Each team would be responsible for their respective microfrontend, ensuring that components remain cohesive and modular. By doing so, you maintain a modular structure, prevent tightly-coupled dependencies, and facilitate better team collaboration.

2. Implement a Shared Design System

To maintain consistency across microfrontends, implement a shared design system, style guide, or UI component library. This approach ensures a cohesive user experience and promotes collaboration between teams.

Consider the design system used by Airbnb: their unified design language helps maintain a consistent look and feel across their platform, even as different teams work on individual components.

3. Optimize Performance

Microfrontends can introduce potential performance issues, such as increased bundle sizes or slower loading times. Using optimization techniques like lazy loading, code splitting, and resource caching would help you reducing these risk factors.

For instance, the sports streaming platform DAZN optimizes performance by lazy-loading microfrontends only when required, reducing initial load times and providing a smoother user experience.

4. Streamline Cross-Component Communication

Effective communication between microfrontends is crucial. Establish clear protocols and interfaces for communication, ensuring components remain loosely coupled and can evolve independently.

In the case of a banking application, a microfrontend responsible for displaying account balances might need to communicate with another microfrontend handling transactions. Using custom events or shared APIs, these components can exchange information while maintaining their independence.

5. Develop a Robust Testing Strategy

Ensure the quality and reliability of your application by developing a comprehensive testing strategy that includes unit, integration, and end-to-end tests for each microfrontend.

Suppose a team is responsible for a microfrontend handling user registration in a social media platform. They should perform unit tests on individual components (e.g., input validation), integration tests to verify correct interaction with other components (e.g., database access), and end-to-end tests to confirm the overall user registration flow.

6. Encourage Team Collaboration

While microfrontends enable team autonomy, strong communication and collaboration between teams are essential to prevent silos and ensure alignment across the application. Establish regular sync-ups, shared documentation, and collaborative planning sessions to foster a healthy team dynamic.

In the Spotify example mentioned in the first part, autonomous development teams (known as “squads”) work on separate components. However, they maintain regular communication and alignment through shared documentation, collaboration tools, and cross-squad meetings.

Design pattern

Implementing microfrontend architecture requires careful consideration of various design patterns to ensure a successful integration. Here, we discuss several design patterns that can help you build a scalable, maintainable, and efficient microfrontend architecture:

Composition Pattern:

The composition pattern focuses on the arrangement and organization of microfrontends in a way that allows them to work together seamlessly. One way to achieve this is by using a microfrontend orchestrator, like single-spa or Module Federation (Webpack ), which acts as a central point for loading, unloading, and coordinating microfrontends.

Shared Design System Pattern:

To maintain a consistent user experience across microfrontends, use a shared design system, style guide, or UI component library. This pattern ensures that each microfrontend adheres to a unified design language, regardless of the underlying technology.

In this code section we see how we can use a UI button over all others microfronts(Next article we’ll see the full implementation)

// SharedButton.js (React)
import React from "react";

export const SharedButton = ({ onClick, children }) => (
  <button className="shared-button" onClick={onClick}>
    {children}
  </button>
);

// Usage in a React microfrontend
import { SharedButton } from "@app/shared-design-system";

const App = () => {
  return (
    <div>
      <SharedButton onClick={() => console.log("Clicked!")}>
        Shared Button
      </SharedButton>
    </div>
  );
};

Event-based Communication Pattern:

Microfrontends should communicate with each other in a loosely-coupled manner. The event-based communication pattern achieves this by using a global event bus, custom events, or shared APIs for exchanging information between microfrontends.

This pattern allows components to remain autonomous while still being able to interact with one another when needed.

// EventBus.js
class EventBus {
  constructor() {
    this.events = {};
  }

  on(event, callback) {
    if (!this.events[event]) {
      this.events[event] = [];
    }
    this.events[event].push(callback);
  }

  emit(event, data) {
    if (this.events[event]) {
      this.events[event].forEach((callback) => callback(data));
    }
  }
}

export const eventBus = new EventBus();

// Microfrontend A - Emitting an event
eventBus.emit("itemAddedToCart", { productId: 1, quantity: 2 });

// Microfrontend B - Listening for an event
eventBus.on("itemAddedToCart", (data) => {
  console.log(`Item added to cart: ${JSON.stringify(data)}`);
});

Container Pattern:

The container pattern involves creating a “container” component that manages the loading and unloading of microfrontends based on user interactions or application state. This pattern can help optimize performance by ensuring that only the necessary microfrontends are loaded at any given time.

Server-side Composition Pattern:

In this pattern, the server is responsible for composing the final HTML page by aggregating content from different microfrontends. This can be achieved using Edge Side Includes (ESI), server-side template, or even custom server-side logic. The server-side composition pattern can be particularly useful for optimizing performance and improving initial page load times.

Cross-cutting Concerns Pattern

This pattern addresses the shared concerns and functionality across microfrontends, such as authentication, logging, or analytics. By creating shared libraries or services that handle these cross-cutting concerns, you can promote re-usability, maintainability, and consistency across your application.

let’s see an overview of this architecture using a code sample

// AuthService.js
class AuthService {
  constructor() {
    this.isLoggedIn = false;
  }

  login(username, password) {
    // Perform authentication logic, e.g., API call
    // If successful:
    this.isLoggedIn = true;
  }

  logout() {
    this.isLoggedIn = false;
  }

  isAuthenticated() {
    return this.isLoggedIn;
  }
}

export const authService = new AuthService();

// Usage in a microfrontend
import { authService } from "@app/shared-services";

if (authService.isAuthenticated()) {
  console.log("User is authenticated");
} else {
  console.log("User is not authenticated");
}

You may develop a microfrontend architecture that is scalable, maintainable, and efficient by applying these design patterns. These patterns can help you overcoming the difficulties involved in integrating various technologies and guaranteeing a consistent user experience throughout your application.

Conclusion

Although microfrontends have many benefits, it’s important to keep in mind that they might not be the best choice for every project. Before deciding to use this architectural pattern for your particular application, it is crucial to carefully assess the requirements and limitations of that application.

As you continue to explore the world of microfrontends, we encourage you to stay up-to-date with the latest developments, tools, and techniques in this ever-evolving domain. By doing so, you will be well prepared to assess and create web apps that not only address the users’ current business needs but also endure throughout time if you accomplish this. Happy coding and enjoy programming!!

By arriving here you’ll be able to start implementing our first microfrontend application. On the next part we gonna implement our first application using this approach. See you in a week !!