Revolutionizing Frontend Development: Exploring Micro Frontends for Scalable and Efficient Web Applications

In recent years, web application development has undergone significant transformations - the main focus has been shifted to delivering a seamless user experience centered around the customer. Previously, web applications were typically structured as a single monolithic entity. As they got more complex, such architectures became more challenging to maintain and scale, and a single monolithic entity evolved into a decoupled backend and frontend monolith. The separation between the user-facing presentation layer and the backend processes has become the prevailing approach in software development which is often used even nowadays. Typically, this involves two teams of developers: frontend developers responsible for creating the visual elements of the application, such as the layout, design, and user interface components, and backend developers responsible for web services, APIs, and other backend systems that handle data storage, business logic, and integrations with other systems. 

This pattern demonstrates its effectiveness for small-scale development with small teams, allowing for simple testing and debugging and lower initial costs. However, the approach retains its monolithic nature even with the division into two sizable chunks of frontend and backend codes. So, unless the project and the team are small, developers continue facing such downsides of a monolithic structure as limited deployment flexibility, challenges in introducing new technologies or features, scalability issues, and high entry barriers for new developers who may struggle to understand the project's logic.

The introduction of microservices, first discussed at a workshop of software architects in 2011, has further revolutionized the development process. With microservices, the monolithic backend was broken down into smaller, autonomous components to be managed by specialized teams. Based on this architectural approach, each service, such as, for instance, a search service or payment service, has its own codebase, which enables independent deployment, testing, and scaling of each service without affecting the other services in the system. Microservices often communicate with each other using HTTP/HTTPS requests and third-party APIs. Teams use either an API Gateway or a backend for the frontend (BFF) service to integrate microservices with the front end. An API Gateway acts as a centralized entry point for a group of microservices, providing a single point of entry for the frontend application to interact with the microservices. It can help to simplify frontend development by abstracting away the complexity of the microservices and providing a unified interface for the frontend application. On the other hand, a BFF service extends the API Gateway pattern by adding an additional layer between the microservices and the frontend client types. It introduces multiple gateways, each tailored to the needs of a specific frontend client type. It can provide greater flexibility and customization in how the front end interacts with the microservices.

Microservices have already become a popular architectural approach across different industries and company sizes. World-known companies like Netflix, Amazon, Uber, Airbnb, and LinkedIn have implemented microservices architecture on their websites. This implementation has enabled them to develop, test, and deploy new features and services at a faster pace, enhance performance and scalability, and bolster their platforms. According to the DZone 2022 Microservices survey, 93% of developers who took part in this survey work for an organization that runs microservices. In contrast, the same study of 2021 indicated only 74% of such developers.

So, the adoption of microservices has significantly changed the backend process. But frontend codebases have remained mainly static despite their increasing complexity, hindering the integration of new features, adoption of new technologies, and scalability of individual components. So in recent years, the idea of dividing the functionalities of an application on the client side started to find its reflection in the adoption of micro frontends. According to the micro frontends architectural approach, web applications are built by breaking down the frontend codebase into smaller, more manageable pieces, representing individual fragments or features of the web page.

Actually, the concept of micro frontends has been around for several years, starting from its first mention in 2016, but it's only recently that it's gained significant popularity. This could be due to the challenges of coordination, the immaturity of the approach, and the fact that it's not always the best solution for every application. However, according to the State of Frontend 2022 report, which surveyed 3703 frontend professionals from 125 countries, almost a quarter of developers has already implemented micro frontends in their work. Some well-known companies such as Spotify, IKEA, Zalando, OpenTable, and eBay have implemented micro frontends on their websites to increase the speed, flexibility, scalability, and efficiency of their development process while providing a better user experience. So, it's worth exploring when micro frontends are the right approach and what benefits they offer.

Micro frontends solve issues that arise with monolithic architectures, allowing for a more efficient development process by organizing teams vertically, wherein each team works with a specific micro frontend focused around a particular business function. Teams can work on different parts of the application simultaneously without disrupting other areas of the codebase, making it especially beneficial for large development teams working on a single product or codebase and where different application parts require different development approaches.

Based on the level of granularity, micro frontends can be classified into two main types: 

1. Page micro frontends represent a complete application page, and each micro frontend encapsulates the entire user interface for a specific page. This approach is suitable when there are clear boundaries between pages of the application and there is little overlap between the functionality of different pages. The benefit of using page micro frontends is that only the micro frontend for the current page needs to be loaded when a user navigates to a new page, which can result in faster load times and a more responsive user interface.

2. Component micro frontends, on the other hand, represent a single UI component or a small set of related components. They can be used to build complex UIs by combining multiple elements. This approach is suitable when there is a lot of overlap between the functionality of different application parts, and it makes sense to split the UI into small, reusable pieces. Common places to implement component micro frontends include the header, footer, search bar, navigation menu, and individual sections of the page that represent distinct functionality or content.

The main benefits of using micro frontends in web application development include the following:

• Scalability: micro frontends allow for greater scalability in web application development. By breaking down the front end into smaller, more manageable pieces, each piece can be scaled independently as needed. It can help prevent the entire application from being affected by a single component's failure, improving overall application stability and reliability.

• No Technology Lock-in: with micro frontends, different teams can work on different application parts, each using the technology or framework best suited to that particular component, allowing flexibility and avoiding the risk of being stuck with a legacy framework for the entire app lifecycle. It allows for more significant innovation and experimentation in the development process, leading to more diverse and effective solutions. However, it is still essential for programmers to exercise caution in selecting frameworks and engaging in discussions with other teams.

• Faster development cycles: micro frontends can also help speed up the development cycle of web applications. With each micro frontend module developed and deployed independently, updates and changes can be made more quickly without affecting other application parts. It allows for faster iteration and deployment cycles, leading to more rapid innovation and improvement in the application.

• Easier maintenance: by breaking down the front end into smaller, more manageable pieces, micro frontends can also make it easier to maintain the application over time. Each component can be updated or replaced as needed without affecting other parts of the application. It can help keep the application up-to-date and secure while also making it easier to troubleshoot and debug any issues that arise.

• The lower entry barrier for new developers: micro frontends have a distinct advantage over monolithic UI in that they are easier to comprehend and handle for new developers. Rather than navigating through a complex codebase, newcomers can quickly understand the individual, simplified components of a micro frontend architecture. It can reduce the time it takes for new developers to become productive members of the development team.

However, despite all the benefits, implementing micro frontends also comes with its own set of challenges. Some of the potential challenges include the following:

• Increased complexity: by breaking down the front end into smaller, more manageable pieces, micro frontends can increase the overall complexity of the application. Each micro frontend module may have its own technology stack, design patterns, and development processes. As a result, it can be more challenging to integrate different modules into a cohesive whole. So, it is important to note that although all micro frontends are independent, they require a certain level of coordination and communication between the different teams to ensure that all of them are integrated into a seamless application experience. 

• Communication: while micro frontends allow teams to work autonomously, it's crucial to have effective cross-team communication to ensure consistency of the big whole. Without clear communication, teams can quickly lose sight of the overall picture while focusing solely on their micro frontend. Micro frontends also require more robust communication channels between different frontend modules, particularly as the number of modules grows, as each module may need to communicate with other modules to share data or coordinate their behavior. 

• Versioning: micro frontends can also present challenges with versioning. Since each module is developed and deployed independently, ensuring that all modules are running the same version of the application can be difficult. It can result in compatibility issues and other problems that may be hard to troubleshoot and resolve.

• Increased infrastructure needs: micro frontends may require additional infrastructure to support because each module may need to be deployed separately, potentially requiring separate hosting environments and other resources.

• High Initial Investments: A micro-frontend project involves the cost of gathering and maintaining multiple frontend teams, along with the need for management staff to plan the work, coordinate efforts, and ensure effective communication among teams.

So, taking into account the benefits and challenges mentioned above, we can conclude that micro frontends may not be the best fit for small and simple websites, as well as for projects where it's unclear how to divide the application's functionality into distinct and independent parts. In the former case, they can overcomplicate things that can be easily done with a monolithic approach. In the latter case, they can disorganize the work structure and add complexity with fewer gains. On the contrary, micro frontends would be particularly useful in some situations, namely:

• Large applications with multiple teams: with large applications, it can be challenging for various teams to work on the same codebase efficiently. Micro frontends allow teams to work independently on specific application parts without worrying about affecting other parts of the codebase.

• Legacy codebases: In applications with legacy codebases, updating or changing the entire codebase can be a hard task. Micro frontends can help break down the codebase into smaller, more manageable pieces, making updating or changing specific application parts easier.

• Applications with different technologies: In applications where different parts of the front end require different technologies or frameworks, micro frontends can help by allowing each component to be developed and deployed independently, using the technology or framework that is best suited to that particular part.

• Modular applications: In applications where specific functionalities or features can be developed as standalone modules, micro frontends can help by allowing these modules to be developed and deployed independently without affecting the rest of the application.

Now that we have a clear understanding of what micro frontends are and when they are beneficial to be implemented, you may be curious about how individual micro frontends integrate into a unified application.

In conclusion of the current topic, we would like to stress that micro frontends are gaining popularity for a reason. They offer a promising solution to the limitations of traditional monolithic frontend architectures. Micro frontends will likely become even more popular as the web continues to evolve. However, it's crucial to remember that this approach may not be suitable for every project. Micro frontends work best for larger applications where the benefits of modularity and scalability outweigh the added complexity.