Senior Mobile Software Engineer

Upstart is an AI lending marketplace committed to reducing borrowing costs for Americans. The Senior Mobile Software Engineer will design and build scalable mobile applications using React Native, collaborating with cross-functional teams to deliver high-quality user experiences and improve the mobile platform.

Responsibilities:

• Build and maintain user-facing features in our React Native mobile apps across iOS (and Android, as we expand)
• Design and implement mobile components and subsystems that are performant, maintainable, and scalable across platforms
• Collaborate with product and design teams to scope, implement, and launch features that align with user and business needs
• Contribute to platform improvements, including tooling, testing strategies, CI/CD, and performance monitoring
• Work with backend engineers to define mobile-specific APIs and improve client-server integration patterns
• Identify and resolve performance or reliability issues in the mobile experience
• Participate in code reviews, architecture discussions, and technical planning to raise engineering quality across the team
• Support a strong mobile engineering culture through mentorship, collaboration, and a focus on continuous improvement

Requirements:

• Have 6+ years of professional software development experience, including meaningful contributions to production mobile apps
• Have experience building in React Native, and familiarity with at least one native platform (e.g., Swift/Objective-C for iOS or Kotlin/Java for Android)
• Understand mobile performance, memory management, and platform-specific constraints
• Communicate effectively with cross-functional partners in product, design, and backend engineering
• Take ownership of your work and are comfortable delivering complex features from planning through release
• Balance speed and quality, and advocate for maintainable, scalable engineering solutions
• Contribute to team culture and engineering practices through feedback, mentoring, and collaboration
• Embrace a growth mindset and enjoy learning from others while helping teammates grow
• Have helped launch or scale a React Native app on the Android platform
• Are comfortable working with TypeScript or custom native modules
• Have experience with mobile analytics, push notifications, deep linking, or A/B testing frameworks
• Have worked in a fast-paced product company where mobile was a primary user touchpoint
• Have contributed to internal tools, processes, or systems that improved mobile developer velocity or code quality