Flutter Developer

xflow; Warszawa; Hybrid; PLN 180,000 - 240,000; Full time

Benefits offered by this job

Flexible hours

Remote/office options

Career growth

Job summary

X-FLOW in Warsaw, Poland, is seeking a Flutter Developer for the Happy Color project and new initiatives. You will build high-quality Flutter apps with pixel-perfect UI, maintain performance, and implement modular architectures across iOS and Android.

Join a creative team with flexible hours, remote/office options, and growth opportunities. The role requires 4+ years of Flutter/Dart experience, strong UI skills, and experience with state management and testing.

Qualifications

• 4+ years of Flutter/Dart experience with widget lifecycle, state management, and animations.
• Experience with pixel-perfect layouts and 60/120 FPS animations.
• Deep understanding of Bloc, Cubit, and Provider patterns and clean architecture.
• Hands-on with performance profiling and optimization using DevTools.
• Ability to integrate Firebase, analytics, in-app purchases, and push notifications.
• Knowledge of Android/iOS ecosystems and platform channels.

Responsibilities

• Develop and maintain high-quality Flutter applications focused 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 with designers and backend engineers to deliver smooth UX on iOS and Android.
• Improve code quality through reviews, refactoring and automated testing.

Skills

Flutter & Dart

State management

Animations

Performance tuning

UI components

Bloc/Cubit/Provider

DevTools profiling

Firebase integration

Platform integration

Unit & integration tests

Tools

Flutter DevTools

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.
• Russian - C1/higher, English - B1+.

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!

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