Flutter Developer

X-FLOW; Województwo mazowieckie; Hybrid; PLN 120,000 - 180,000; Full time

Benefits offered by this job

Flexible hours

Remote/office options

Creative team

Job summary

X-FLOW invites a skilled Flutter Developer to join our flagship Happy Color project and contribute to new mobile ventures. You will build high-quality Flutter/Dart apps with pixel-perfect UI, animations, and robust architecture for both iOS and Android.

Collaborate with designers and backend engineers, optimize performance, and implement tests. We offer flexible hours, remote/office work, and a creative, inclusive culture in a growing mobile game studio.

Qualifications

• 4+ years of Flutter/Dart experience.
• Solid understanding of widget lifecycle and state management.
• Proficiency in Dart (async programming, isolates, generics).
• Experience building custom UI components, pixel-perfect layouts, and smooth 60/120 FPS animations.
• Deep understanding of Bloc / Cubit / Provider and Clean Architecture.

Responsibilities

• Develop and maintain high-quality Flutter applications with a focus on performance, stability, and clean architecture.
• Implement adaptive, responsive UI and complex animations with pixel-perfect precision.
• Design modular and testable architectures.
• Collaborate with designers and backend engineers to deliver smooth UX across iOS and Android.
• Continuously improve code quality through reviews, refactoring, and automated testing.

Skills

Flutter/Dart

State management

Performance tuning

Animations

Unit tests

Tools

Flutter DevTools

Firebase

Platform channels

Job description

X-FLOW is a mobile game development company established in 2018. We gained recognition after the release of Happy Color, the most popular digital coloring book and one of the most successful ad-driven mobile apps in the world.

We are looking for a Flutter Developer for our flagship project, Happy Color, and for development of new projects.

Key Responsibilities:

• Develop and maintain high-quality Flutter applications with a focus on performance, stability, and clean architecture.
• Implement adaptive, responsive UI and complex animations with pixel-perfect precision.
• Design modular and testable architectures.
• Identify and fix performance bottlenecks (scrolling, rendering, rebuilds).
• Collaborate closely with designers and backend engineers to deliver smooth UX across iOS and Android.
• Continuously improve code quality through reviews, refactoring, and automated testing.

Requirements:

• 4+ years of Flutter/Dart experience with solid understanding of widget lifecycle, state management, and animation system.
• Strong knowledge of Flutter SDK (animations, adaptive UI, rendering, performance tuning).
• Proficiency in Dart (async programming, isolates, generics, mixins).
• Experience building custom UI components, pixel-perfect layouts, and smooth 60/120 FPS animations.
• Deep understanding of Bloc / Cubit / Provider and clean architectural principles (SOLID, Clean Architecture).
• Hands-on experience with Flutter DevTools for performance profiling and optimization (scroll, rebuilds, memory).
• Ability to integrate Firebase, analytics, in-app purchases, and push notifications.
• Understanding of Android/iOS ecosystems and platform channels for native integrations.
• Experience writing and maintaining unit and integration tests.

What We Offer:

• Competitive salary and benefits package.
• Opportunity to work with a talented and passionate team in a creative and dynamic environment.
• Flexible working hours and remote/office work options.
• Career growth and professional development opportunities.
• A fun and inclusive company culture that celebrates diversity and creativity.

Join us and let’s create great content together!