Revolutionizing Front-End Development: A Deep Dive into Micro Front-End Architecture

What Are Micro Frontends?

Micro frontends represent an architectural approach to frontend web development, where in an application is divided into smaller, independent features known as micro frontends. This strategy aims to enhance the delivery quality and efficiency of teams working on frontend code.

Each micro frontend operates with its own codebase, dependencies, automated test suite, and deployment pipeline. Typically, a single frontend team owns and manages each micro frontend, developing, testing, and deploying it independently from other features. This autonomy boosts the efficiency of the development process.

The concept of micro frontends gained recognition relatively recently, with Michael Geers introducing the term in 2016. It gained further attention later that year when it was featured in ThoughtWorks Technology Radar. Despite its recent formal introduction, frontend developers have long utilized this architectural style to achieve modularity, independent deployment, and scalability in frontend development.

Difference Between Microservices and Micro Frontends

A micro frontend can be seen as the frontend equivalent of microservices in backend architecture.

Microservices involve breaking down a backend monolith into various loosely coupled components (services), each handling distinct functionalities. This approach allows independent development, testing, and deployment of backend services.

Micro frontends , on the other hand, apply a similar concept to frontend development. A web application is divided into smaller, autonomous modules called micro frontends. These modules are independently developed and can operate with separate repositories, responsibilities, and deployment pipelines. However, unlike microservices, it is not always necessary to assign each micro frontend to an individual team.

The challenge and key aspect of both microservices and micro frontends lie in integrating these independent modules to ensure they function together seamlessly. For micro frontends, the ultimate goal is to create a cohesive, unified website that delivers a smooth and personalized user experience, despite being composed of independently developed modules.

A Good Example of Micro Frontends

Initially, web applications were constructed as monoliths due to their simplicity and ease of management. In a monolithic architecture, all code, business logic, and data access layers are tightly integrated and deployed as a single unit. This setup includes a single repository, build process, deployment pipeline, and infrastructure, which simplifies development and testing.

However, as the complexity of web applications increased, the monolithic approach became less practical. For large-scale websites like Amazon, PayPal, Ryanair, and Netflix, where multiple development teams work on various functionalities, modifying or adding new features became challenging. Making changes in a monolithic system often impacts the entire application, making it difficult to maintain high quality. Additionally, issues such as scalability and fault tolerance arise since scaling a monolithic application requires scaling the entire system, which can be costly and inefficient.

To address these challenges, microservices and micro frontends were introduced, offering a more modular and flexible approach to web development. By breaking down a website’s monolithic architecture into smaller, manageable services, developers can independently scale and deploy components.

In the context of micro frontends, the application's frontend is divided into distinct sections, each developed and deployed independently. This modularity makes the overall system more resilient and easier to maintain, providing a more efficient and scalable solution for modern web applications.

How Micro Frontend Works: Integration Approaches

To understand micro frontends, it helps to start with monolithic architecture, named after a solid block of stone that represents a single entity. In software development, a monolithic architecture describes an application managed by a single team, with databases, backend, and frontend all integrated and shared.

As applications became more complex, developers recognized the advantages of separating backend and frontend development. Applying the microservices approach to the backend allowed applications to become more scalable, resulting in loosely coupled services that could be independently deployed.

The natural progression was to apply this approach to the frontend. Monolithic frontends had become bottlenecks for rapid development, as any change affected the entire application, leading to longer compilation times.

Moreover, issues of ownership and responsibility can arise when multiple teams work on an application with a monolithic architecture. For example, if two teams release significant features simultaneously and performance statistics drop by 30%, it becomes challenging to pinpoint responsibility. If everyone is responsible, no one is responsible.

This is where micro frontend architecture becomes advantageous. The application is divided into isolated, self-managed, and independent parts, which are then integrated to function as a single cohesive website. This modular approach allows for more efficient and scalable development.

Exploring Common Micro Frontend Integration Approaches

Micro frontend integration approaches can be visualized as a slider. On one end, the application is less separated, resulting in fewer micro frontend benefits but a simpler setup. This approach requires only a single version of the micro frontend framework and one library version. As you move the slider toward greater separation, the application becomes more complex to set up and maintain. However, this increased complexity allows you to fully realize the benefits of micro frontends.

Let's explore some of the most common approaches for integrating micro frontends.

Routing: Loading Separate Applications

This approach involves separating the application based on routing, where each route loads a completely independent application, including its own framework bundles. In this scenario, the infrastructure acts as a shell, with redirects between applications managed through mechanisms like an API gateway or CDN.

This method is ideal for page-level integration when different teams manage different pages of the application, with each micro frontend functioning as a single-page application.

Routing can be implemented using HTML links, which causes the page to reload with each navigation, allowing data sharing only through query parameters, session storage, or persisted data in the database.

From a user's perspective, navigating to a specific URL triggers the central routing application to determine which micro frontend should handle the request based on the URL. The selected micro frontend is then loaded and displayed, while others remain hidden.

For seamless rendering without page reloads, a shared application shell or meta-framework like single-span can be used. The app shell includes minimal HTML, CSS, and JavaScript, providing an instantly rendered static page even while data is still being fetched from the server. Subsequent interactions and updates load dynamically, avoiding page refreshes.

NPM Packages Approach

In this approach, each micro frontend is released as an individual package using the node package manager (NPM). The shell application then lists and incorporates these packages into the overall application. While this method offers a simple setup, it also has drawbacks, such as the requirement for single dependency versions and the inability to release a micro frontend without a corresponding shell release, potentially creating cross-team dependencies and hindering updates.

Iframe-Based Micro Frontend

This method embeds each micro frontend within its own iframe, with a single-page application (SPA) acting as the container. Essentially, an HTML document is placed inside another HTML document, and the SPA coordinates communication between the iframes.

Though iframes provide a good level of separation, this relatively older approach comes with challenges, such as ensuring security and data sharing.

Web Components

In this approach, each micro frontend is built as an isolated component that can be deployed independently as a .js file. The application then loads and renders these components in designated placeholders within the layout. Web components instruct the browser when and where to create a component.

The downside is that each web component can be large and needs to bundle its own framework version, so while many components can be separated, performance must be carefully monitored.

Module Federation

Module Federation is a more modern approach, introduced with Webpack 5 in 2020, and it helps make all micro frontend components appear as a single application. This method sits in the middle of the separation spectrum for micro frontends.

Module Federation allows micro frontends to be loaded at runtime into a shell application without any build-time dependency, requiring only defined integration contracts. This is particularly useful for customizing pages for specific clients. For instance, a website may load a ‘checkout’ module from a common pack for most clients and a customized one for specific clients, possibly developed by the client’s team. Module Federation enables runtime configuration changes for micro frontends.

Benefits of Micro Frontends

Splitting a monolithic application into loosely coupled modules is a complex task that only makes sense if the micro frontend approach addresses specific issues you are facing. Without such problems, the effort may not be justified. However, here are some of the key benefits that micro frontends can offer:

Faster Deployment and Better Release Management

Unlike a monolithic frontend, where a single team is responsible for implementing all new functionalities and features, micro frontends allow smaller, autonomous teams to work simultaneously on deploying various functions and features. This significantly reduces development time and accelerates release cycles.

Multiple Teams with Different Responsibilities

Each team manages its own micro frontend, which is self-contained. They can build, test, deploy, and update it independently. In a monolithic architecture, if Team A is ready for a release but Team B needs more time, Team A has to wait. This dependency is eliminated with micro frontends, as each team operates independently without relying on others.

Technology Freedom

Each micro frontend can be implemented using different technology stacks since they are autonomous pieces of software. This allows teams to choose their own technology stack based on their expertise and experience.

Easy Scaling

Micro frontends provide a significant advantage in terms of scalability. Each feature can be scaled independently, making the process more cost-effective and time-efficient compared to scaling a monolithic application.

Continuous Deployment

Breaking a monolithic frontend into smaller, independent components enables incremental updates without affecting the entire application. It also makes it easier to roll back a single component to a previous version, improving team collaboration by reducing bottlenecks and increasing scalability, among other benefits.

When to Use Micro Frontends

Project Size: Medium to Large

Adopting a micro frontend approach is particularly beneficial for medium to large projects involving multiple teams working on distinct features. This architectural style enhances scalability and allows for faster feature rollouts without the risk of impacting the entire website.

Productivity: A Key Priority

Micro frontends allow independent teams to work separately on different features, significantly boosting overall productivity. Teams can develop, test, and deploy their components simultaneously, streamlining the development process and improving efficiency.

Micro Frontends Benefits for Different Roles

Micro frontend architecture offers various advantages to different roles within an organization, beyond just software developers and testing engineers.

Benefits for Finance Directors

• Faster Releases, Reduced Costs: Micro frontends are developed autonomously, leading to more efficient development and quicker releases. With smaller, more manageable codebases, developers make fewer mistakes and work faster, reducing development and maintenance costs and providing better budget control.
• Better ROI: Autonomous teams working on micro frontends accelerate the development process and shorten release cycles. This rapid deployment and release strategy enhances time-to-market, reduces costs, and improves return on investment (ROI), resulting in better financial outcomes for the organization.

Benefits for Marketing Managers

• Improved Customer Experience: Reduced coupling between pages offers greater flexibility for marketing managers to experiment with new features that enhance customer experience. Micro frontend architecture allows for faster feature launches and easy A/B testing to determine the most effective strategies.
• Increased Conversion Rates: Micro frontends can improve conversion rates by delivering a more personalized and seamless user experience. The marketing department can implement targeted content and messaging on specific pages or features more easily, boosting engagement and conversion rates.

Benefits for Product Owners

• Improved Productivity and Control: Micro frontend architecture provides better control over the development process. Product owners can closely monitor non-functional requirements, such as page performance, and quickly identify the responsible team for any bugs or failures. This leads to faster feature development and testing.
• Faster Time-to-Market: Smaller, independent frontend components allow for more focused development, parallel work, and incremental releases, reducing the time needed to bring new features to market. Quick iteration on features ensures the product adapts to changing business requirements.

Benefits for CTOs

• Greater Flexibility and Scalability: Independent deployment and scaling enable CTOs to experiment with new technologies and frameworks without disrupting the entire application. Micro frontends support rapid iteration on frontend features and quick responses to changing business needs.
• Long-Term Maintainability: Micro frontend architecture improves maintainability by dividing the application into smaller, more focused parts. This approach simplifies the codebase, making it easier to understand and update, thereby reducing the risk of accumulating technical debt.

Challenges of Using Micro Frontends

While micro frontends offer numerous benefits, they are not always the ideal solution for every frontend architecture. It's important to understand and address the challenges associated with this approach before deciding to adopt it.

Payload Size

Micro frontends duplicate dependencies and bundle frameworks and libraries, increasing the web app's payload size. However, despite this challenge, web pages using micro frontends often download faster than those using monolithic architecture.

Potential solutions include careful caching of resources, selective dependency selection, and separating rarely used pages.

Cross-Page Communication

Implementing and maintaining communication between micro frontends can be challenging, especially when separate pages need to communicate with each other. For example, one part of the application may need to be notified by the host or other micro frontends about user interactions that require changes, refreshes, or actions.

Design Differences

When separate teams work on each micro frontend, they may not have a holistic view of the website, leading to pages that appear patched together and inconsistent in terms of style and user experience (UX/UI).

To address this, common components, a style guide that all teams can consult, or improved communication between teams can be helpful.

Operational Complexity

Adopting a micro frontend approach introduces operational complexity, as it involves more repositories, tools, build/deploy pipelines, and infrastructure to ensure everything works together seamlessly.

When Not to Use Micro Frontends

Small Project Size

For small and simple websites, implementing micro frontends may be excessive and could unnecessarily complicate the development process. Monolithic architecture may be more suitable in such cases.

High Risk of Poor Communication

If there is a high risk of duplicating specific implementation methods among separate teams, it may be wise to reconsider implementing micro frontends. Starting with a monolithic approach and migrating to micro frontends later could be a better option.

Before deciding on micro frontends, carefully consider the following questions:

• Will the micro frontend approach address the current pain points in the website development process?
• What specific benefits do you hope to achieve with a micro frontend approach?
• Are you comfortable with decentralized decision-making regarding tooling and development practices?
• How will you ensure a minimum level of quality, consistency, and governance across your many independent frontend codebases?

Conclusion

while micro frontends offer several advantages, including faster deployment, better release management, and improved productivity, they also come with challenges. These challenges include payload size issues, cross-page communication complexities, potential design differences, and operational complexities.

It's important to carefully evaluate whether micro frontends are the right choice for your project. Factors such as project size, risk of poor communication, and the need for centralized control should be considered when making this decision. While micro frontends can be beneficial for medium to large projects with multiple teams and complex features, smaller projects may find monolithic architecture more suitable.

Ultimately, the decision to adopt micro frontends should be based on a thorough understanding of your project's needs and goals, as well as a clear assessment of the challenges and trade-offs involved.