Context: Microservices Architectures (MSA) enhance deployment velocity and service autonomy, but traditional End-to-End (E2E) User Interface (UI) testing often reintroduces systemic coupling, leading to slow feedback cycles and high-test flakiness. This friction undermines the core benefits of MSA.

Objective: This research proposes and evaluates a novel, Consumer-Driven Contract (CDC) testing framework—the CDC-UI Hybrid Model—to strategically replace brittle E2E tests for verifying UI-to-backend integration in MSA environments. The goal is to harmonize testing across service boundaries and the presentation layer, accelerating the feedback loop.

Methodology: The study introduces a two-layer contract strategy: standard service-to-service CDC, complemented by a dedicated UI-Consumer Contract where the UI layer defines its expectations of the Backend-for-Frontend (BFF)/API Gateway. A simulated MSA case study was used to compare a baseline E2E-heavy approach against the proposed CDC-UI hybrid model, measuring key indicators such as test execution time, flakiness rate, and defect detection efficacy.

Results: The implementation of the CDC-UI Hybrid Model yielded a notable reduction in overall integration test execution time and a significant decrease in the test suite's non-deterministic flakiness. The approach successfully shifted the detection of UI-backend integration faults earlier in the development pipeline, correlating with a lower Defect Escape Rate.

Conclusion: The CDC-UI Hybrid Model provides a highly effective and pragmatic solution for validating UI integration in microservices. It aligns strategically with modern testing practices, dramatically improving test stability and accelerating the feedback loop, thereby preserving team autonomy and realizing the velocity potential of distributed architectures.