Principal Software Engineer

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!

Upstart’s Mobile team is in the midst of a transformation—from a scrappy, embedded model into a world-class, scalable engineering platform. As we expand our iOS app and launch Android, our need for dedicated backend expertise has never been greater.

You’ll be the first backend engineer embedded within the mobile team, working alongside React Native developers and product partners to shape foundational systems for engagement, messaging, and performance. This is a highly influential role with the opportunity to define backend architecture in support of Upstart’s mobile-first evolution.

• Architect scalable, reusable backend systems that power critical mobile features, including push notifications, data synchronization, and cross-device user flows
• Shape the long-term backend strategy for mobile, reducing ad-hoc and duplicated efforts across teams
• Act as a technical bridge—translating mobile needs into backend capabilities and unblocking delivery velocity
• Drive architectural alignment across teams and domains, advocating for scalable patterns that support mobile growth
• Identify and resolve cross-functional technical challenges that span platform, product, and infrastructure boundaries
• Mentor engineers across mobile and backend teams, introducing sustainable practices and improving system maintainability
• Contribute directly to Upstart’s ability to scale its mobile engagement and retention—impacting both user experience and business performance

• 6+ years of backend engineering experience, including designing and scaling distributed systems
• Deep experience with service-oriented architecture, system design, and API development for mobile applications
• Proven ability to influence technical direction across teams and communicate architectural tradeoffs to stakeholders
• Experience collaborating with mobile teams or supporting mobile-first features at scale
• Strong communication and collaboration skills, especially in environments with competing priorities
• Proficiency in at least one backend language (e.g., Ruby, Go, Kotlin) and fluency in cloud infrastructure patterns
• Demonstrated success operating without authority in complex, cross-functional organizations

• Prior experience building systems that support mobile clients (e.g., push notifications, offline sync, background jobs)
• Experience working in a hybrid mobile architecture (e.g., React Native + native codebases)
• Exposure to both platform and product engineering challenges
• Familiarity with mobile-specific performance and reliability concerns
• Background in mentorship or technical leadership across multiple teams
• Passion for designing elegant, sustainable systems that scale with product ambition

This role is available in the following locations:
Remote, San Mateo, Columbus, Austin.

This team operates across all U.S. time zones.

This team has regular on-site collaboration sessions. These occur 3 days per quarter at an Upstart office. If you need to travel to make these meetups, Upstart will cover all travel related expenses.

• Competitive Compensation (base + bonus & equity)
• Comprehensive medical, dental, and vision coverage…