Abstract
Modern software systems often follow a microservice architecture, where each service is responsible for a specific business capability. While this provides modularity and scalability, it introduces challenges when multiple services must be queried to produce a unified result — particularly in reporting or data aggregation use cases. This paper introduces a novel architectural concept titled Backend for Backend (BFB), a dedicated backend service designed to aggregate and orchestrate data from multiple other backend services. BFB simplifies access to scattered data sources, reduces code duplication, and provides a central point for backend-to-backend communication.
1. Introduction
As microservices become a standard architectural pattern, systems are increasingly composed of loosely coupled services, each owning a distinct set of responsibilities. While this improves maintainability and scalability, it often introduces a pattern of repetitive logic when higher-level services (e.g., reporting services) require access to data scattered across several underlying microservices.
For example, consider the following services:
-User Calls Service — handles and stores information about user phone calls.
-User Emails Service — manages user email data.
-User SMS Service — stores and processes user text message data.
Now suppose we have services such as:
-Admin Report Service
-Manager Report Service
-User Report Service
Each of these reporting services requires access to data from the above-mentioned services. Implementing this data fetching logic in every reporting service leads to code duplication, maintenance overhead, and inconsistent behavior.
This is where Backend for Backend (BFB) comes into play — a service that acts as an intermediary layer between internal backend services, aggregating and serving data through a unified interface.
2. Problem Statement
In typical microservice ecosystems, when multiple services need to interact with the same set of data providers, the following issues arise:
— Code Duplication: Each consumer service implements the same data-fetching logic.
— Tight Coupling: Changes in data provider services require updates across all consumer services.
— Inconsistency: Different consumer services may handle data aggregation or transformation differently.
— Performance Issues: Redundant external calls from multiple services can increase latency and system load.
3. The BFB Solution
3.1 Definition
Backend for Backend (BFB) is a dedicated service layer designed to serve other backend services. It does not directly serve frontend clients or end-users. Instead, its primary role is to aggregate, normalize, and serve data from multiple internal microservices, thereby centralizing the logic that would otherwise be replicated across the system.
3.2 Conceptual Architecture
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4. Use Cases
4.1 Reporting Services
BFB allows reporting modules like Admin Report, Manager Report, and User Report to retrieve a unified data object without knowing the underlying structure or number of services involved.
4.2 Cross-Service Data Composition
In cases where data must be joined or enriched from multiple services (e.g., call logs with user metadata from a different service), BFB handles this internally.
4.3 Simplified Service Contracts
By abstracting the details of multiple services behind a single interface, BFB simplifies the API contracts for its consumers.
5. Benefits
– Reduced Duplication: BFB centralizes shared logic, eliminating redundancy across services.
— Improved Maintainability: A single point of update for service integration changes.
— Consistent Aggregation: Ensures that data aggregation is standardized across different use cases.
— Decoupling: Consumer services are insulated from changes in the underlying services.
6. Implementation Considerations
– Service Discovery: BFB should be able to dynamically discover the underlying services it depends on, using service registry patterns (e.g., Eureka, Consul).
— Data Caching: To reduce response times and load on backend services, BFB can employ intelligent caching strategies.
— Error Handling: Graceful degradation strategies should be implemented in BFB to handle partial service failures.
— Security: BFB must authenticate and authorize backend consumers, and optionally, enforce downstream service security.
7. Potential Drawbacks
– Single Point of Failure: Use load balancing and failover strategies with BFB.
–Increased Latency: Apply parallel calls and caching where possible.
–Overhead in Maintenance: Apply clear service boundaries and unit testing.
8. Conclusion
Backend for Backend (BFB) provides a strategic solution to a common architectural pain point in distributed systems. By serving as an internal aggregation and orchestration layer, BFB significantly improves maintainability, reduces code duplication, and creates a clean separation of concerns. It embodies the principles of reuse, abstraction, and decoupling — key traits of scalable software architecture.
9. Future Work
– Integration with event-driven architectures (e.g., Kafka) for async aggregation.
-GraphQL layer on top of BFB to enable flexible data querying.
-AI-based dynamic aggregation optimization.
References
1. Newman, Sam. Building Microservices, O’Reilly Media, 2015.
2. Richardson, Chris. Microservices Patterns: With examples in Java, Manning Publications, 2018.
3. Martin Fowler — Microservices. https://martinfowler.com/articles/microservices.html
4. Spring Cloud Documentation. https://spring.io/projects/spring-cloud
5. API Gateway vs. Backend for Frontend (BFF). https://docs.microsoft.com/en-us/azure/architecture/patterns/backends-for-frontends
