Micro-frontends for dummies
Tags: frontend, beginners, tutorial, webdev
Published: 2023-04-24 19:00:00

## First thing first.
I wanted to shout a great "THANK YOU" to Luca Mezzalira for his awesome book _Building Micro-Frontends: Scaling Teams and Projects, Empowering Developers_. I was not payed nor asked form him but wanted to say his book is an awesome resource if you want to dig into the micro-frontend world.

Another thing: Let me know, by commenting or liking the post, if you want to read more from me about this topic! I'd love to make this a series based on the most important concepts!

## Introduction
Microservices have become a popular architecture for building modern, scalable applications. However, as applications have become more complex, developers have also started to adopt micro-frontends. Micro-frontends are a way to decompose a front-end application into smaller, more manageable pieces, similar to how microservices decompose back-end systems. In this article, we will explain what micro-frontends are and why they are important.

## What are Micro-frontends?
Micro-frontends are a way of breaking down a front-end application into smaller, more manageable pieces, each with its own distinct functionality. This is done by splitting the application into multiple "micro-frontends," each of which can be developed, tested, and deployed independently of the others. Micro-frontends communicate with each other through well-defined interfaces, allowing them to work together to provide a cohesive user experience.

## Why are Micro-frontends Important?
Micro-frontends have several benefits over traditional monolithic front-end architectures. First, they enable faster development cycles, as each micro-frontend can be developed and deployed independently of the others. This allows teams to work in parallel, speeding up development times. Second, micro-frontends can improve scalability, as they allow different parts of the front-end application to scale independently of each other. This means that the application can handle increased traffic more easily, without having to scale the entire application at once. Finally, micro-frontends can make it easier to maintain and evolve front-end applications over time, as changes can be made to individual micro-frontends without affecting the rest of the application.

## How do Micro-frontends Work?
Micro-frontends can be implemented in several ways. One approach is to use iframes to load each micro-frontend as a separate page, each with its own HTML, CSS, and JavaScript. This approach can be simple to implement but can have performance issues and challenges with cross-domain communication. Another approach is to use client-side routing to load each micro-frontend as a separate component within a single page. This approach can have better performance and allow for more seamless communication between micro-frontends.

## Challenges of micro-frontends
While micro-frontends offer many benefits, they also come with some challenges. One of the most significant challenges is managing the communication between the different modules. Since each module is a separate application, it's important to have a well-defined contract for how they communicate. Otherwise, it can quickly become chaotic and difficult to manage.

Another challenge is the increased complexity of deployment and infrastructure. With multiple frontend applications, there are more moving parts to manage, which can make it more difficult to deploy and scale the application.

## Communication between micro-frontends
To communicate between micro-frontends, there are a few different options. One is to use a message bus or event stream to send messages between the different modules. This approach allows for loose coupling and allows different teams to work independently. Another option is to use an API gateway to aggregate requests from the different modules and provide a unified API for the frontend. This approach can help to simplify the frontend and make it easier to manage.

## Tips and tricks for micro-frontends
To get the most out of micro-frontends, it's important to follow some best practices. One of the most important is to define a clear contract for communication between the different modules. This contract should be well-documented and enforceable.

Another best practice is to use a common design language and style guide across all the different modules. This helps to ensure consistency and makes it easier for users to navigate the application.

Finally, it's important to have a solid testing and deployment strategy in place. Since there are multiple applications to manage, it's important to have a clear process for deploying, testing, and rolling back changes.

## Bonus Tip: Backend-for-frontends and micro-services
When building a microservices architecture, it's common to have several microservices serving different business domains. Each microservice might require a different set of data and provide different operations to the front-end clients. To handle this complexity, we can use the Backend-for-Frontends (BFF) pattern, where a dedicated service acts as a proxy between the front-end clients and the microservices. The BFF service provides an optimized API for each client type, reducing the coupling between the front-end and the microservices. This approach also allows for better scalability and performance, as the BFF service can aggregate data from multiple microservices and cache the results.

## Conclusion
Micro-frontends are an increasingly popular architecture for building modern front-end applications. By breaking down applications into smaller, more manageable pieces, micro-frontends enable faster development cycles, better scalability, and easier maintenance. There are several ways to implement micro-frontends, and the right approach will depend on the specific requirements of the application. However, by adopting micro-frontends, teams can build better front-end applications that are more scalable, more maintainable, and easier to evolve over time.

## What do you think?
Have you ever worked with micro-frontends? What are your thoughts on this approach to building front-end applications? Let me know in the comments below!