BFF — Backend (as a friend) For Frontend: Pros and Cons

In my previous article, we delved deep into the complications of integrating APIs with mobile apps, especially when dealing with a monolithic system tailored for web clients. We highlighted the challenges of ensuring a one-size-fits-all API to meet the demands of various client types, including mobile apps, voice assistants, and third-party services. Offering a solution to these challenges, we introduced the concept of the Backend For Frontend (BFF) design pattern. BFF acts as an intermediary layer between microservices and each client type, facilitating a tailored API experience for each. This means mobile clients can enjoy an optimized experience without unnecessary data bloat. The power of the BFF doesn’t stop there; it streamlines maintenance, offers better API versioning per frontend, and can enhance system performance. With examples, we showcased how the BFF structure can be gradually implemented into existing systems and the advantages of fault tolerance that it offers. In this article, we will review the pros and cons of Backend for Frontend and how they may affect our business needs.

How can we assess the business value of BFF?

Building on our in-depth exploration of the Backend For Frontend (BFF) design pattern, let’s delve into its significant impact on the business realm:

Enhancing User Experience: Just as BFF tailors experiences per client interface, businesses can similarly augment the user journey, catering even to niche market micro-segments. This nuanced approach invariably boosts customer satisfaction by offering features that resonate with every user type.

Amplified Business Agility: Mirroring the flexibility that BFF offers in API integrations, businesses can swiftly construct proofs-of-concept, allowing them to gauge product-market resonance efficiently. This agility not only saves time but also curbs unwarranted expenditures.

Strategic Financial Operations: Drawing parallels with BFF’s ability to tailor data extraction, businesses can astutely monitor costs and evaluate financial trajectories of distinct features. Such insight-driven financial modeling aids in discerning the profitability of features, and guiding decisions on their continuity or discontinuation. Unfortunately, maintaining BFF solutions is not always effective.

Upholding Coding Excellence: Upholding Coding Excellence: In line with BFF's focus on ensuring clean API gateways for diverse clients, maintaining a quality codebase becomes paramount. Good coding practices pave the way for enhanced scalability, adapting to fluctuating market conditions. Moreover, it fosters an environment where new developers can seamlessly comprehend and contribute, furthering project progression even when under the hood we have a legacy system.

Pros and Cons

The Backend for Frontend (BFF) pattern is an architectural pattern that is used in software engineering, particularly in the context of building user-facing applications. Here are some pros and cons of employing the BFF pattern:

Pros:

Tailored APIs: BFF enables the creation of client-specific APIs that can be tailored to each user interface, leading to optimized data retrieval and processing, which ultimately results in better performance and user experience. Separation of Concerns: It helps in maintaining a clear separation between the backend and frontend, which can make the system more organized and easier to manage. Simplified Frontend: With BFF, the complexity in the frontend can be significantly reduced as a lot of data processing can be moved to the backend, making the frontend codebase simpler and easier to work with. Faster Iteration: BFF can lead to faster development and iteration on the frontend as developers can quickly build and modify APIs to meet the changing requirements of the frontend. Code Reusability: Common backend logic can be shared among different frontends, leading to better code reusability and consistency across different platforms (web, mobile, etc.).

Cons:

Increased Complexity in Backend: BFF can add an additional layer of complexity in the backend as developers need to manage multiple BFFs for different frontends. Potential for Code Duplication: There is a potential for code duplication if common functionalities are implemented separately in each BFF. Operational Overhead: Managing multiple BFFs can lead to higher operational overhead in terms of deployment, monitoring, and scaling. Potential Performance Issues: If not designed carefully, the additional layer of BFF can introduce latency or performance issues. Learning Curve: There might be a learning curve for teams that are new to the BFF pattern, which could slow down development initially.

By employing the Backend for Frontend pattern, organizations can better tailor backend services to meet the specific needs of each frontend application, which can be beneficial in projects with multiple client-facing applications having different requirements and user experiences. However, the added complexity and operational overhead could be a downside, and it requires a well-thought-out design to ensure that the benefits outweigh the disadvantages.

When should we use BFF?

There are typical situations when the usage of BFF can help us to design better systems and have the right decoupling for them, so let's review some cases:

Microservices: Just as BFF tailors API experiences per client interface, within a microservices architecture, each microservice can champion its own BFF. This engenders unparalleled flexibility, allowing each service to have a backend meticulously tailored for its specific client. BFF also manages multiple microservices and serves one API.

Crafting Micro Frontends: In scenarios where the frontend is fragmented into smaller, nimble components, each can be paired with its BFF. This cultivates enhanced separation of concerns and agility.

For Architectural Decoupling: In tandem with architectural paradigms like micro frontends, BFF fosters a harmonized and modular system landscape. Which may help to build more reliable and effective systems. This is good when we know that our backend solution may evolve a lot in the future. The layer on top of it can reduce the need for changes on the client side. This is very useful when our clients are distributed and not fully controlled by us like mobile apps (the update is managed by the user) or 3rd party solutions.

Complex UI Requirements: For applications with complex UIs that require data from multiple sources or services, a BFF can consolidate and adapt data efficiently, simplifying the frontend logic.

Cross-Platform / Multiplatform Solutions: When architecting multiple client-oriented applications, the need for distinct backends surfaces to champion a clear separation of concerns. Even when we use multiplatform solutions like Flutter or Kotlin Multiplatform, a dedicated backend layer can be helpful to support multiple versions or as a cache and reducer for the data and amount of them.

Better Performance: BFF, much like its role in optimizing data transfers for specific clients, can bolster performance and scalability by curtailing and caching data payloads between client and server.

Championing Agile Development: Echoing BFF’s ability to streamline client-specific interactions, it aids in simplifying development workflows. This ensures client applications evolve without inadvertently stirring the backend. It can also be helpful for A/B testing or different release times of some features for specific clients. Additionally, when front-end teams need to move quickly without being bound by backend release cycles, BFF allows them to define and modify their data needs independently. This ensures faster iteration and deployment.

When should we avoid BFF Pattern?

In light of our profound exploration of the Backend For Frontend (BFF) design pattern, it’s equally essential to identify scenarios where its incorporation might not be the ideal solution:

Simple Systems with Few Clients: If your system has a limited number of client types (e.g., only a web client) and does not anticipate diversification in the near future, introducing a BFF might be overkill.

Uniform Data Needs Across Clients: When all client interfaces require the same data in the same format without any transformation, a BFF layer might introduce unnecessary complexity.

Compact Crew: BFF, while powerful, can usher in added complexity. Each client application necessitates its dedicated backend, potentially overwhelming smaller teams or nascent startups.

Assessing Product Intricacy: Much like BFF’s intent to offer client-specific backend experiences, there are instances where a product’s client-side design doesn’t delve deep into complexities. In these cases, crafting a backend bespoke to a particular client interface could be redundant.

The RESTful solution is OK: Sometimes, the architectural landscape calls for the well-trodden path of the traditional RESTful API — a framework that remains a dominant force in web API designs.

GraphQL: If you’re already using technologies like GraphQL, which allows clients to request exactly the data they need, introducing a BFF might be redundant. In some cases when for example you do not manage the clients BFF can be built for 3rd party services and provide them more restricted API like REST. This will avoid a situation in which one of these clients does a very heavy query to the server via GraphQL.

Latency Issues: Parallel to BFF’s layer that bridges specific clients and backends, there are applications that prioritize fast client-to-microservice interactions. These scenarios aim to circumvent potential lags birthed by extra communication layers amidst decoupled microservices. If we have a lot of reads from the server then BFF can cache them and speed up the responses, but for fast save transactions we should rather avoid that additional layer and its delay.

Do we have alternatives for BFF?

Delving deeper into our exploration of Backend For Frontend (BFF), it’s imperative to acquaint ourselves with alternative architectures that have found their niche in the realm of web development:

GraphQL: Developed by Facebook, GraphQL is a query language for APIs and a runtime for executing those queries against your data. Unlike REST, which exposes a fixed set of endpoints for each resource, GraphQL allows clients to request exactly what they need. This flexibility often reduces the need for a BFF since the frontend can specify its data requirements.

API Gateway: An API Gateway acts as a reverse proxy that accepts API calls, aggregates the various services required to fulfill them, and returns the appropriate result. It can handle request routing, composition, and protocol translation, often used in microservices architectures to unify multiple services.

OpenAPI / Swagger: This is a specification for building APIs. OpenAPI allows for defining a standard, language-agnostic interface to RESTful APIs. With tools like Swagger UI, it can provide interactive documentation, client SDK generation, and API discoverability.

The Serverless Paradigm: Transcending traditional norms, this architecture doesn’t tether itself to a perpetual server or its cluster, but instead activates code on-demand, curbing costs and complexities.

When considering an alternative to BFF, it’s essential to analyze the specific requirements and constraints of your project. The ideal solution will often depend on factors like the complexity of your client interfaces, the nature of your backend services, the scalability requirements, and the desired user experience.

Conclusion

In summary, while the BFF design pattern offers a compelling solution for many contemporary web development challenges, it’s crucial to approach it (and its alternatives) with a discerning eye. Understand your project’s unique needs, anticipate its future growth, and weigh the pros and cons of each approach. In doing so, you’ll be well-equipped to chart a path forward that maximizes efficiency, scalability, and user satisfaction.