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