Back-end for Front-end Pattern in Ecommerce
Introduction
The world of ecommerce development is rapidly evolving, and new tech and software patterns are rapidly emerging. One of these technologies that have gained popularity in recent years is headless architectures.
Headless architecture is an approach where the front-end and back-end of an application are decoupled, allowing for greater flexibility, scalability, and the ability to deliver better user experiences across various platforms.
Building headless applications can be challenging especially if you’re dealing with multiple microservices and APIs. One solution to this problem is using a Back-end for Front-end (BFF) pattern. Let’s explore the BFF pattern, its benefits, and how it can help build more maintainable and efficient headless systems.
What is a Back-end for Front-end (BFF) Pattern?
The Back-end for Front-end (BFF) pattern is a custom API that sits between the back-end microservices APIs and the front-end application. Instead of the front-end application being responsible for calling all the microservices and processing the results, it makes a single call to the BFF. The BFF then calls the relevant microservices and structures and formats the responses from those microservices, delivering the response back to the front-end application in a nicely formatted way.
Example BFF Implementation
Consider a scenario where an ecommerce business needs three different front-end applications - a website, mobile apps, and an in-store app. Each of these apps has unique functionality requirements that need to be addressed in their own back-end architecture. For instance, the in-store app only requires features such as searching for products and viewing products, while the website is a full fledged ecommerce store, implementing product recommendations, payment gates and a blog section for SEO purposes. The mobile apps may implement marketing push notifications but don’t require having a “Blog” section.
To address these different requirements, we can build separate back-ends for each use case. This allows us to easily change the functionality we expose to each application (and ensures that we can meet the unique needs of each front-end). With a separate back-end for the in-store app, we can ensure that it has access to the specific features it needs, while the website and mobile apps can use the remaining services.
By building separate back-ends for each of the use cases, we can easily customise the functionality we expose to each of the applications, allowing us to have three different teams - one for the website, one for the mobile apps, and one for the in-store app. Each team can focus on their specific use case, resulting in more efficient development and maintenance. Additionally, this approach can help to reduce complexity and improve scalability, ensuring that the ecommerce platform can meet the demands of its users.
Benefits of BFF Pattern
Reduces front-end complexity
A BFF acts as a simple interface between the front-end and the microservices/APIs, making it easier to maintain front-ends and reducing their complexity. Without the BFF, front-end applications need to interact directly with the microservices/APIs, which means front-end developers need to have a deep understanding of how those services work, greatly increasing the complexity of your front-end component.
Separates front-end Requirements from back-end concerns
A BFF separates front-end requirements from back-end concerns, making it much easier to maintain the application. The application knows less about your API structure, meaning it is much more resilient to API changes. For example, if a microservice API is updated or replaced, the front-end code only needs to be concerned with the interface provided by the BFF, making it less likely to cause issues with the front-end code.
Better error handling
In a point-to-point approach, error messages would typically be passed directly to the front-end, where it would be displayed to the user. This is where BFF can intercept these errors and provide a more meaningful message to the user and can also prevent sensitive data from being exposed to potential attackers.
Maintainability
Application development can be separated into different teams far more easily when using BFF. Different teams would be responsible for BFFs, meaning they have much more control over how they consume the APIs. For example, one team could be responsible for the BFF of a mobile app, while another team is responsible for the BFF of a web app, each of them doing releases independently.
Enhanced Performance
By making requests to the microservices API directly from the front-end, each of these requests would involve establishing a network connection, sending a request, waiting for a response, and parsing the data. BFF allows the front-end to do batch calls to microservice APIs and return a more concise set of formatted data. This way, the number of network steps decreases and the amount of data transmitted can also be trimmed, which results in smaller payloads and fewer network steps.
Best Practices for Implementing BFF Pattern
When building headless application architectures using a BFF, there are a few things to consider and avoid. Firstly, you must avoid building self-contained APIs in the BFF. All of your self-contained APIs should be in the API layer.
Secondly, you need to avoid duplication, one BFF is for one application. For example, the user experience in a mobile app, whether it's iOS or Android, will pretty much be the same. And in this case, you should only have one BFF for all your mobile apps.
Thirdly, you should avoid relying too heavily on the BFF. All of your features and your security should be held within either the front-end or your APIs. The BFF is just there to fill a gap, rather than a means to add new features or services to your application.
Alternatives
While BFFs are a useful pattern for implementing headless architecture and microservices, there are other alternatives that can be used depending on the specific needs of the project like building an API Gateway, using GraphQL or adopting a monolithic architecture, it’s really up to you to decide.