Senior Flutter Developer

About On The Spot: We bring startups and disruptive tech companies to the local market, offering engineers the opportunity to work on innovative, high-impact products. Join us and become a member of their R&D team while we take care of employment, HR support, a benefits package, and an enjoyable work environment. About the team: Finonex is a company building modern mobile trading and financial applications across multiple brands from a shared Flutter codebase. The team focuses on creating accessible, secure, and user-friendly trading experiences powered by cutting-edge technology, supported by 24/7 service. About the role: We are looking for a strong, hands-on Senior Flutter Developer to join our Mobile R&D team and help build our mobile trading applications. This is a hands-on engineering role. You'll design and build high-quality features across Android and iOS, working within an established multi-flavor architecture and to a high engineering standard, as part of a team led by our Mobile Team Lead. The ideal candidate takes strong ownership of their work, writes clean and maintainable code, and thrives in a fast-moving, regulated financial environment. Please note that candidates for this position are expected to work in alignment with the Israeli team: Sunday-Thursday — work days, Friday-Saturday — days off. Responsibilities: Software Development Design, develop, test, and maintain high-quality features for Android and iOS in Flutter.Write clean, well-structured, testable code that follows the team's architecture, patterns, and coding standards.Contribute to integrations such as real-time market data, charting, analytics, and third-party financial SDKs.Work within the existing multi-flavor / multi-brand build and release process.Troubleshoot and fix production issues, and help keep the apps performant and stable. Quality & Testing Participate actively in code reviews - both giving and receiving constructive feedback.Write unit, widget, and integration tests to keep quality high.Contribute to app reliability and observability (crash-free rates, performance). Collaboration & Delivery Collaborate closely with Product, Design, Backend, and QA to deliver business objectives.Deliver predictably within sprints, with honest estimation and clear communication of progress and risks.Communicate proactively and clearly in English with a distributed, cross-country team. Requirements: 5+ years of professional software development experience.4+ years of hands-on Flutter development on production applications (Flutter as a primary, day-to-day skill - not occasional or secondary).Strong command of Dart and modern state management (BLoC, Riverpod, and Provider).Solid working experience within multi-flavor / multi-environment Flutter apps.Working knowledge of native Android and iOS - build configuration and platform-channel / SDK integration.Experience with REST APIs and real-time communication (WebSocket or similar).Strong ownership, autonomy, and problem-solving skills.Excellent written and verbal English — a must (daily communication with the Israel-based team).Availability to work Sunday-Thursday, aligned with the Israeli team — a must. Nice to have: Experience in fintech, trading, forex/CFD, financial services, or another regulated industry.Experience with the Firebase suite (Crashlytics, Remote Config, Performance, Analytics).Experience with product analytics / attribution (e.g. Mixpanel, AppsFlyer).Experience with charting libraries (e.g. ChartIQ) and engagement SDKs (e.g. Braze).Familiarity with FVM, monorepo workflows, and GitLab CI.Experience with automated / integration testing and AI-assisted development tools.Experience working in distributed / international teams. Benefits: Paid vacation — 20 business days per year, 100% sick leave payment (up to 10 days), 5 sick days per year;Equipment provision;Partially compensated educational costs (courses, certifications, attendance of professional events, etc.);Care package: Luxmed health insurance;English classes 2 times a week (online);MultiSport card 50% reimbursement company/employee;Full legal and accounting support in Poland if requested.