Sr. Software Engineer II, Mobile

What You’ll Do

We are seeking a highly skilled and experienced Engineer specializing in Flutter to join our Mobile Engineering Team. As a Sr. Mobile Engineer II, you will lead mobile architecture, mentor engineers, and deliver scalable, high-performance applications that power a seamless cross-platform experience. You will influence technical direction across teams, set a high standard for engineering excellence, and drive end-to-end quality and reliability in our mobile products.

• Own the life cycle of features through testing, debugging, documenting, releasing, and monitoring
• Take part in daily standups and regular team-wide meetings to discuss current and upcoming tasks
• Participate in the technical roadmap for mobile architecture, frameworks, and tooling
• Participate in design reviews, architecture discussions, and performance optimization efforts across iOS and Android
• Implement robust, maintainable Flutter solutions that follow best practices for state management, dependency injection, and reactive programming
• Collaborate with Product and Design teams to iteratively improve the user experience on mobile platforms
• Investigate issues, mitigate them, and recommend preventative measures
• Improve observability, monitoring, and crash analytics to ensure product stability and quality
• Help foster a culture of technical excellence, innovation, and collaboration

• 6+ years of professional software engineering experience
• 2+ years of hands‑on Flutter and Dart experience in production environments
• Understanding of mobile architecture, state management, and design patterns (BLoC, MVVM, Clean Architecture)
• Experience maintaining testing strategies for Flutter applications, spanning unit, widget, integration, and end‑to‑end levels
• Familiarity with building CI/CD automation for mobile delivery
• Understanding of RESTful APIs, Web Sockets, and offline data handling
• Familiarity optimizing performance, reliability, and user experience across diverse devices
• Ability to perform in a team environment adopting agile principles
• Strong written and verbal communication skills
• Strong grasp of OOP design principles

• Knowledge of native iOS (Swift) and Android (Kotlin/Java) integration
• Experience with fintech or trading platforms
• Contributions to open‑source frameworks or SDKs

The salary range for this role is $ – $ USD. In addition, this position will also receive an annual target bonus of 12%. Bonus pay at Ninja Trader is based on individual performance (50%) as well as company/team performance (50%).

This role is based in Chicago, IL. Remote flexibility may be available for exceptional candidates in certain states.

• In‑office Tuesday through Thursday, with remote work on Mondays and Fridays
• 20 additional flex remote days annually
• 5 company‑wide office‑optional weeks tied to major holidays

• Generous PTO
• 7 paid holidays annually + 5 conditional holidays annually
• 1 service day annually
• 401(k) with 3.5% company match
• Life and disability insurance covered 100% by Ninja Trader

We are committed to equal employment opportunity regardless of race, color, ancestry, religion, sex, national origin, sexual orientation, age, citizenship, marital status, disability, gender, gender identity or expression, or veteran status. We are proud to be an equal opportunity workplace.