Professional work Confidential

Online-banking modernization

Led frontend and BFF work within the modernization of an online-banking platform, helping move legacy functionality toward a micro-frontend architecture while improving API boundaries, testing, accessibility, and delivery quality.

Context: Online-banking modernization
Organization: EmbedIT
Role: Senior Fullstack Developer
Period: 2025–2026

Product screenshots and source code are not publicly available. This case study therefore focuses on my role, architectural decisions, and engineering process.

Problem

Legacy functionality needed to move toward a micro-frontend architecture without weakening the boundaries between the user interface and downstream banking services.

Frontend delivery depended on clear API contracts and a BFF layer that could absorb service-level complexity instead of leaking it into product code.

Constraints

The product and implementation details are confidential.

Changes had to preserve integration stability while meeting testing and accessibility requirements.

My responsibility

Led frontend and BFF work within the modernization effort.

Built BFF controllers, mappers, and service orchestration.

Designed API contracts and coordinated integrations across downstream services.

Contributed unit, integration, E2E, and accessibility testing.

Improved CI/CD flow and code-review standards.

Approach

Kept service-specific response shapes behind explicit mappers and contracts.

Treated accessibility and automated testing as delivery requirements rather than final-stage cleanup.

Used code review and CI feedback to keep changes understandable across frontend and backend boundaries.

Key technical decisions

Keep downstream complexity out of the UI

Multiple services exposed different response shapes and operational concerns.

Use the BFF as an explicit integration boundary with controllers, mappers, and orchestration that presented stable contracts to the frontend.

The BFF adds code and ownership, but keeps product UI logic focused and easier to test.

Build quality into the migration

Modernization work can reproduce legacy behavior while introducing new integration and accessibility risks.

Cover the work with unit, integration, and E2E tests, and include accessibility requirements in implementation and review.

The migration had clearer release checks and stronger delivery discipline.

Outcomes

Helped move legacy functionality toward a micro-frontend architecture.

Established clearer API and BFF boundaries for frontend delivery.

Strengthened testing, accessibility, CI/CD, and review practices around the work.

Reflection

In sensitive systems, architecture is not only component structure. It is also error semantics, ownership, traceability, and confidence in how changes are released.

Open-science tooling