About Upstart Upstart is the leading AI lending marketplace partnering with banks and credit unions to expand access to affordable credit. By leveraging Upstart's AI marketplace, Upstart-powered banks and credit unions can have higher approval rates and lower loss rates across races, ages, and genders, while simultaneously delivering the exceptional digital-first lending experience their customers demand. More than 80% of borrowers are approved instantly, with zero documentation to upload. Upstart is a digital-first company, which means that most Upstarters live and work anywhere in the United States. However, we also have offices in San Mateo, California; Columbus, Ohio; and Austin, Texas. Most Upstarters join us because they connect with our mission of enabling access to effortless credit based on true risk. If you are energized by the impact you can make at Upstart, we’d love to hear from you! The Role As a Principal Mobile Software Engineer at Upstart, you’ll sit at the intersection of mobile platform and product development. You’ll lead efforts to scale and refine our React Native architecture while partnering closely with product, design, and backend teams to ship impactful, high-quality features. You’ll define technical direction, improve developer experience, and mentor other engineers — all while helping Upstart grow into a truly mobile-first company. This is a highly cross-functional role with visibility across the stack and deep influence on how we build and deliver mobile software. You’ll play a key role in shaping how mobile is built and scaled at Upstart — helping define mobile as a core product pillar and driving impact across teams and surfaces. The Team The Mobile team at Upstart is building the future of our user experience. Today, we have a live iOS app built in React Native, and we’re actively planning our Android expansion. Our platform is still early-stage, which means there's a huge opportunity to influence architecture, best practices, performance, and product velocity. We move quickly, collaborate tightly with backend and design, and care deeply about quality — not just in the UI, but in the systems that power a great user experience.