Senior Mobile Engineer Fully Remote in Spain or Poland We are working with a leading online scheduling platform designed to simplify the process of coordinating meetings and events. Founded over 18 years ago, it helps individuals and teams avoid the\ "back-and-forth\" of email scheduling by allowing users to propose multiple time slots and let participants vote on their availability. Responsibilities of the role: Develop Cross-Platform Features: Build and maintain high-performance mobile features using Flutter and Dart for seamless iOS and Android experiences. Integrate Native Modules: Leverage Android (Kotlin/Java) and iOS (Swift) expertise to develop custom plugins and optimize performance. Optimize API Communication: Implement reliable data fetching and error handling using GraphQL and REST for backend integration. Enforce Code Excellence: Write clean, well-tested code and lead code reviews to reinforce mobile development best practices. Collaborate Cross-Functionally: Partner with Backend, Product, and Design teams to shape GraphQL schemas and technical roadmaps. Mentor & Lead: Support junior engineers by sharing expertise in architecture, Flutter patterns, and native integrations. Requirements of the role: 5+ years of professional software engineering experience, including at least 3+ years in mobile development with a history of shipping and maintaining production apps Expert-level proficiency in Flutter and Dart Strong proficiency in a native mobile platform, preferably Android (Kotlin/Java), with bonus points for iOS experience (Swift/Objective-C) Significant hands-on experience integrating mobile apps with backend services via GraphQL (e.G., Apollo, GraphQL-Flutter), with a strong understanding of best practices. Experience applying modern mobile architecture patterns—such as Provider, Bloc/Cubit, Riverpod, MVVM, or Redux—to build scalable, maintainable apps. Proficiency with state management, dependency injection, performance profiling, and writing comprehensive unit and widget tests in Flutter.