Principal Software Engineer, Cash Line

The Team

Cash Line is Upstart’s new always on revolving credit product designed to expand access to responsible, fairly priced credit. Instead of a traditional rewards driven credit card model, Cash Line rethinks how credit is structured and priced, using AI driven underwriting to better separate risk and reduce the need for cross subsidized rewards.

We are a small, senior engineering team operating like a startup inside Upstart. The team owns the product end to end, from consumer facing experiences in the mobile app to the backend systems that power underwriting, pricing, servicing, and capital markets integrations.

This is a high ownership environment. The codebase is new. The architecture is still being shaped. You will work closely with product, growth, finance, compliance, and capital markets partners to build a category defining credit experience.

We are building with generative AI as a core capability from day one, both in the customer experience and in how we build and operate the product internally.

How you’ll make an impact:

• Design and build the core backend systems that power a new revolving credit product used directly by consumers.

• Own distributed services that support underwriting, pricing, line management, transactions, and servicing with high reliability and observability.

• Translate complex product and economic requirements into scalable technical systems, balancing speed, risk, and long term maintainability.

• Partner closely with machine learning engineers and data teams to productionize models and integrate AI driven decisioning into real time user flows.

• Collaborate with mobile engineers to deliver seamless consumer facing features, ensuring backend systems are optimized for real world usage patterns.

• Work across the full lifecycle of credit, from consumer acquisition and onboarding through funding, servicing, and capital markets distribution.

• Shape foundational architectural decisions in a greenfield environment, while thoughtfully integrating with systems from Upstart’s mature lending platform.

• Contribute to a Gen AI first product strategy, helping define how generative AI enhances user experience, internal tooling, automation, and operational workflows.

• Raise the bar for engineering quality through strong API design, data modeling, observability, testing, and operational rigor.

Minimum Qualifications 

• 8+ years of experience building and operating backend systems in production, ideally for consumer facing applications.

• Strong experience designing distributed systems and event driven architectures, including real world handling of retries, idempotency, fault tolerance, and failure modes.

• Proficiency in an object oriented language such as Python, Java, Kotlin, C#, or Ruby, and experience building and maintaining APIs and service oriented architectures.

• Experience shipping consumer facing features end to end, with a strong understanding of latency, reliability, and user impact.

• Ability to work effectively in ambiguous, zero to one environments where requirements evolve quickly.

• Strong cross functional collaboration skills and comfort working closely with product, finance, compliance, and other business stakeholders.

• Active use of AI tools in engineering, with a forward-looking perspective on how AI is reshaping software development.

• Exceptional communication and collaboration skills; able to align teams and advocate for high-impact solutions across functions.

Preferred Qualifications

• Experience in fintech, credit, payments, or other regulated financial systems.

• Familiarity with revolving credit, line management, transaction processing, or ledger based systems.

• Experience building systems that sit at the intersection of consumer products and capital markets infrastructure.

• Background working with ML driven pricing, underwriting, or risk systems.

• Hands on experience leveraging generative AI in product features or internal engineering workflows.

• Experience on small, high ownership teams where engineers are responsible for architecture, implementation, and operational excellence.

• Passion for building products that expand access to credit and improve financial outcomes for underserved consumers.

Position Location - This role is available in the following locations: Remote, San Mateo, Columbus, Austin 

Time Zone Requirements - This team operates across all U.S. time zones.

Travel Requirements - 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.

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