Senior Software Engineer (Android) - Service Agreement

Rate: 135 – 170 PLN/hour (B2B)

We are looking for an experienced Senior Software Engineer to join Flix on a freelance/service agreement basis (B2B contract). This is a contractor engagement for a seasoned professional who doesn’t just write code but thinks about the entire mobile ecosystem, including performance, quality, scalability, UX, and testing.

Scope of Services

Bring expertise in building high-quality, scalable, and user-friendly Android applications to enhance the Flix passenger journey — optimizing key features such as post-booking and home page experiences, while incorporating innovative solutions that drive mobile development excellence.

About the Engagement

Design, develop, and maintain high-quality Android applications with a focus on scalability, performance, and user experience.

Support closely iOS, Backend, and feature teams to align on feature specifications and ensure seamless cross-platform integration.

Drive technical improvements across the entire codebase, including architecture enhancements and codebase modernization.

Enhance app performance and user experience through UI optimizations, accessibility compliance, and improvements in battery usage, memory management, and load times.

Leverage analytics & metrics to make data-driven decisions, optimizing performance and engagement based on user behavior and app health.

Write clean, maintainable, high quality and testable code, ensuring high test coverage through unit, integration, and UI tests to guarantee reliability.

Actively contribute to improving CI/CD pipelines, app stability, and release processes, driving faster delivery and higher productivity.

Maintain clear, up-to-date technical documentation, including API specs, architectural decisions, and code comments, fostering transparency and knowledge sharing within the stakeholders.

About You

6+ years of Android development experience with a proven track record of building high-quality, user-facing Android apps.

Strong expertise in Kotlin (Jetpack Compose, MVVM, Coroutines), with a deep understanding of Android architecture and best practices.

Hands-on experience with performance optimizations, background services, memory management, and smooth user interactions (UI, animations).

Experience with testing (unit, integration, UI testing) and a strong commitment to writing testable, maintainable code.

Ability to drive technical strategy, ensuring high standards in code quality, performance, and scalability.

Understanding of SOLID principles and software architecture patterns.

Experience working with CI/CD pipelines and automated deployment systems (GitLab, Fastlane, Docker).

Experience with Firebase SDK, including Firebase Analytics, Remote Config, and Crashlytics.

Customer-centric approach with a focus on delivering great user experiences.

Cooperation model

Cooperation based on a service agreement (B2B/freelance contract), not an employment contract.

You will operate as an independent contractor, responsible for delivering agreed services and submitting invoices

Location: open for contractors based in Poland