Intro to BFF Pattern

A Developer's Best Friend

Oct 08, 2024

Sometimes in software development, all you need is a BFF.

In software development, the term BFF, which stands for Backends-for-Frontends, refers to a design pattern where dedicated API gateways are created for each device or interface type.

For example, you create a separate BFF for web browsers, mobile apps, or public/partner APIs.

Each BFF acts as a specialized layer between the client and the underlying services, tailoring the API to the specific needs of the client.

You can play around with the diagram on Eraser.io

Key Characteristics of BFFs

Dedicated API Gateway: Each BFF serves as a dedicated API gateway for a specific device or interface type. It encapsulates the logic and requirements specific to that client type.
Customized Functionality: BFFs can handle various functionalities beyond simple API routing. They can perform tasks such as:
1. rate limiting,
2. authentication,
3. header sanitization
4. cache control
Decoupling from Lower-Level Services: By implementing BFFs, the logic specific to different client types is abstracted away from the lower-level services. This allows the services to focus on their core functionality while the BFFs handle client-specific requirements.

Advantages of the BFF Pattern

Implementing the BFF pattern offers several advantages:

Resiliency: By having separate BFFs for different client types, the impact of a faulty deployment or issue in one BFF is isolated to that specific client. Other clients remain unaffected, improving overall system resiliency.
Autonomy: Each BFF can be optimized according to the specific needs of the client it serves. For example, mobile clients may prefer larger responses to minimize network calls, while web clients may prioritize smaller payloads. BFFs provide the flexibility to cater to these varying requirements.
Development Speed: The resiliency and autonomy provided by BFFs boost developer confidence and enable faster development velocity. Teams can work independently on different BFFs without the fear of impacting other clients.

Disadvantages of the BFF Pattern

While the BFF pattern offers benefits, it also has some drawbacks to consider:

Code Duplication: When multiple BFFs share common functionalities, such as authorization or business logic, there is a risk of code duplication across the BFFs. This can lead to maintenance challenges and inconsistencies.
Complexity: As the BFFs become responsible for more glue-logic and orchestration of services, they can become more complex over time. Managing this complexity requires careful design and maintenance.
Proliferation of BFFs: Developers may be tempted to create a new BFF for every slightly different scenario, leading to an excessive number of BFFs. This can result in increased complexity and maintenance overhead.

Best Practices for Implementing BFFs

To effectively leverage the BFF pattern, consider the following best practices:

Clearly Define Client Requirements: Thoroughly understand the specific requirements of each client type and design the BFFs accordingly. Avoid creating unnecessary BFFs for minor variations.
Minimize Code Duplication: Identify common functionalities across BFFs and consider extracting them into shared libraries or services to minimize code duplication.
Maintain Clear Boundaries: Clearly define the responsibilities of each BFF and ensure they align with the overall system architecture. Avoid overloading BFFs with excessive functionality.
Monitor and Optimize Performance: Regularly monitor the performance of BFFs and optimize them based on client requirements and usage patterns. Ensure efficient resource utilization and scalability.

So - have you used the BFF pattern?