Senior Software Engineer (Mobile Fullstack)

ButterflyMX is on a mission to empower people to open and manage doors & gates from a smartphone. The Senior Software Engineer (Mobile Fullstack) will partner with Product, Design, and Engineering teams to design, build, and evolve APIs and mobile applications, while leading large-scale projects with a customer-first mindset.

Responsibilities:

• Partner with Product, Design, and other Engineering teams to help design, build, and evolve the APIs, services, and mobile applications that power our products
• Architect and build high-performance, cross-platform mobile applications for iOS and Android using React Native, delivering a native-quality user experience from a shared codebase
• Lead large-scale projects from ideation to launch with a customer-first mindset, spanning both mobile and backend layers
• Design, build, and maintain efficient, reusable, reliable, and testable code across the full stack
• Integrate with native device capabilities (push notifications, Bluetooth/NFC for access control, camera, GPS) using native modules and bridging where necessary
• Identify bottlenecks and bugs across mobile and backend systems, devise solutions and propose optimizations for performance, reliability, and user experience
• Work comfortably across front-end, mobile, and back-end layers of the architecture
• Implement patterns and systems allowing for independently deployable full-stack services at a level of granularity appropriate for team composition and business value
• Own the mobile build and release pipeline, including App Store and Google Play submission processes, code signing, and over-the-air update strategies
• Help maintain code quality, organization, and automatization
• Write new and improve current documentation
• Lead by example for other members of the team as a dedicated, passionate, and flexible technologist who is constantly striving to improve code quality, design, and system architecture
• Help define, document, evolve, and evangelize high engineering standards and best practices across mobile and backend development

Requirements:

• 5+ years of professional development experience
• 4+ years of professional development experience in TypeScript, JavaScript
• 2+ years of hands-on experience building and shipping production React Native applications on both iOS and Android
• Strong understanding of React Native internals, navigation patterns (React Navigation), and state management (Redux, Zustand, or similar)
• Experience with mobile app distribution workflows: App Store Connect, Google Play Console, code signing, TestFlight, and OTA updates (e.g., CodePush or EAS Update)
• Strong experience with automated CI/CD pipelines, including mobile-specific CI
• Strong experience working in and advocating for Agile environments
• Deep understanding of testing and what, when, and how to test, including mobile-specific testing strategies (Jest, Detox, or Appium for E2E)
• Extensive experience with developing and maintaining APIs, as well as integrating with 3rd party APIs
• Hands-on experience working in a Distributed/Cloud-based environment (e.g. Amazon EC2/ECS, Lambdas, No-SQL DB, Azure, etc.) within a service-oriented architecture
• Experience working with relational databases and writing SQL queries
• Excellent verbal and written communication and collaboration skills to effectively communicate with both business and technical teams
• Comfortable working in a fast-paced, results-oriented environment
• Motivated by the desire to learn and collaborate, to own and improve, and to focus on what helps the business succeed
• Well versed in the disciplines of security, reliability, and scalability
• Well versed with Agile methodology and who believes in the value of a well written and appropriately defined user story
• User-focused with a keen sense of how your code will impact the user's experience in terms of performance, security, and usability — especially on mobile where latency, battery life, and offline resilience directly affect user trust
• Passionate about frequent value delivery through collaboration with product owners, preferring MVPs and tight build-measure-learn loops to maximize value
• Someone who truly cares about leading and mentoring engineers
• Proven experience with leveraging AI tools in both professional and personal settings. ButterflyMX is an AI-forward organization and the ability to optimize efficiency using AI is crucial in every role
• Experience with Bluetooth Low Energy (BLE) or NFC integrations for physical access control or IoT
• Open-minded approach to choosing the right tool for the job
• Familiarity with real-time communication protocols (WebSockets) for device-to-app interaction
• Experience with React Native performance profiling tools (Flipper, Hermes, React DevTools)
• Contributions to or experience with React Native's New Architecture (Fabric, TurboModules)