Senior Mobile Engineer (Flutter)

About The Opportunity

We are seeking a highly experienced senior Flutter engineer to join our team and help evolve a large-scale, high-traffic mobile application serving both sides of a U.S. marketplace: the consumer experience and the advisor experience.

You will work within a mature production environment that includes real architectural complexity, legacy design decisions, active design system migrations, native platform integrations, and real-time communication features that must perform reliably under challenging network conditions.

The role is heavily focused on Flutter development, with approximately 90% of the work in Flutter/Dart and 10% involving native iOS and Android integrations. We are looking for engineers who have successfully improved and modernized existing mobile applications at scale, not just built new applications from scratch.

As a senior contributor, you will play a key role in technical decision-making, architecture evolution, mentoring, performance optimization, and delivering high-quality user experiences across iOS and Android platforms.

Responsibilities

• Design, develop, and maintain features within a large-scale Flutter application used by thousands of users daily
• Build and optimize performance-sensitive and real-time mobile experiences
• Diagnose and resolve performance issues including frame drops, excessive rebuilds, memory pressure, and rendering bottlenecks
• Use Flutter DevTools, Xcode Instruments, and Android Studio Profilers to investigate and improve application performance
• Integrate native platform capabilities and third-party SDKs through Flutter platform channels
• Develop and maintain native integrations using Swift and Kotlin
• Improve the reliability of real-time messaging and communication features, including reconnect logic, lifecycle management, and event synchronization
• Implement and maintain reusable design-system components with a strong focus on UI quality and animations
• Create and maintain unit, widget, and integration tests while promoting testing best practices
• Contribute to observability, monitoring, error tracking, and production issue resolution
• Participate in architecture discussions, technical planning, and code reviews
• Mentor other engineers and help drive technical excellence across the team
• Collaborate closely with Product and Design teams to deliver accessible, responsive, and user-centric experiences
• Contribute to mobile CI/CD pipelines and release processes for iOS and Android applications

Required Qualifications

• 6+ years of professional experience in mobile application development
• At least 3 years of hands-on experience developing and maintaining production applications with Flutter and Dart
• Deep understanding of Flutter internals, including the Widget Tree, Element Tree, Render Object Tree, rendering pipeline, rebuilds, relayouts, and repaints
• Strong experience optimizing Flutter application performance using Flutter DevTools and profiling tools
• Hands-on experience with state management solutions such as BLoC/Cubit, plus Riverpod or Provider
• Strong knowledge of mobile architecture patterns including Clean Architecture, MVVM, and reactive programming
• Experience modernizing and improving legacy or complex codebases without requiring full rewrites
• Practical experience integrating native iOS and Android functionality through platform channels
• Working knowledge of Swift and Kotlin for debugging and implementing native integrations
• Experience consuming and integrating RESTful APIs and third-party services
• Experience with real-time communication technologies and mobile application lifecycle management
• Strong testing experience using flutter_test, bloc_test, Mocktail, Mockito, or similar frameworks
• Experience implementing quality gates and test coverage practices within CI environments
• Hands-on experience with CI/CD platforms such as Bitrise, Fastlane, GitHub Actions, or Codemagic
• Strong written and verbal communication skills with experience participating in technical decision-making and mentoring engineers
• Bachelor’s degree in Computer Science, Software Engineering, or a related field, or equivalent practical experience

Nice To Have Skills

• Experience building standalone native applications using Swift/SwiftUI or Kotlin/Jetpack Compose
• Experience working on marketplace, two-sided platform, or subscription-based consumer products
• Experience with WebSockets, streaming, or other real-time communication architectures
• Knowledge of feature flagging and experimentation platforms such as LaunchDarkly or Firebase Remote Config
• Experience with mobile observability, crash monitoring, and production incident management at scale
• Knowledge of accessibility standards and mobile accessibility implementation best practices
• Hands-on experience with animation and design system tooling such as Widgetbook, Material 3, Lottie, or atomic design systems
• Experience leveraging AI-assisted development tools such as GitHub Copilot, Claude, Claude Code, or Cursor beyond code completion
• Experience building internal developer tooling, AI workflows, MCP integrations, or engineering automation solutions
• Experience working within distributed or international engineering teams

_Avenue Code reinforces its commitment to privacy and to all the principles guaranteed by the most accurate global data protection laws, such as GDPR, LGPD, CCPA and CPRA. The Candidate data shared with Avenue Code will be kept confidential and will not be transmitted to disinterested third parties, nor will it be used for purposes other than the application for open positions. As a Consultancy company, Avenue Code may share your information with its clients and other Companies from the CompassUol Group to which Avenue Code’s consultants are allocated to perform its services.

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