Senior Application Security Engineer

About Upstart

At Upstart, we’re united by a mission that matters: to radically reduce the cost and complexity of borrowing for all Americans. Every day, we bring creativity, experimentation, and advanced AI to reshape access to credit, helping millions move forward financially with clarity and confidence.

As the leading AI lending marketplace, we partner with banks and credit unions to expand access to affordable credit through technology that’s both radically intelligent and deeply human. Our platform runs over one million predictions per borrower using more than 3,000 signals, powering smarter, fairer decisions for millions of customers. But the numbers only hint at the impact. Every idea, every voice, and every contribution moves us closer to a world where credit never stands between people and their financial progress.

We’re proudly digital-first, giving most Upstarters the flexibility to do their best work from wherever they thrive, alongside teammates across 80+ cities in the US and Canada. Digital-first doesn’t mean distant. We’re intentional about in-person connection through team onsites, planning sessions, and moments that spark creativity and trust. And whether you choose to work primarily from home or collaborate in-person from one of our offices in Columbus, Austin, the Bay Area, or New York City (opening Summer 2026), you’ll have the support to work in the way that works best for you.

If you’re energized by tackling meaningful problems, excited to innovate with purpose, and motivated by work that truly matters, we’d love to hear from you.

Upstart’s Application Security team enables product and engineering teams to build secure products without slowing innovation. We believe security should move at the speed of the business and that safety by design should be embedded throughout the software development lifecycle. Through engineering, automation, and close collaboration, we protect Upstart’s customer-facing products, internal applications, APIs, and AI-enabled systems while maintaining a positive developer experience.

As a Senior Application Security Engineer at Upstart, you will lead application security projects that reduce risk across our products and engineering ecosystem. You will partner with product, platform, data, infrastructure, and engineering teams to identify security risks, review designs, build preventative controls, and drive complex issues through remediation. This role is well suited for an experienced application security engineer who can lead substantial technical initiatives, navigate ambiguity, and deliver durable improvements that raise the security bar across the team and its partners.

• Lead application security projects from planning through implementation, coordinating contributors and dependencies to deliver high-quality outcomes.
• Conduct threat modeling and security architecture reviews for complex customer-facing applications, APIs, distributed services, and AI/ML systems.
• Design and implement secure-by-default controls across the software development lifecycle, including secure coding standards, API protections, automated testing, CI/CD safeguards, and secrets management.
• Partner with engineering teams to identify systemic vulnerabilities, evaluate practical remediation options, and ensure high-risk issues are resolved effectively.
• Build services and automation that improve vulnerability detection, prioritization, validation, and prevention while reducing friction for developers.
• Assess the security of AI-enabled products and developer workflows, including GenAI integrations, agentic systems, model inputs and outputs, sensitive-data handling, and access boundaries.
• Provide technical leadership during high-severity application security incidents, helping determine root causes and drive durable follow-up improvements.
• Improve team effectiveness by contributing to design and code reviews, documenting reusable patterns, mentoring engineers, and helping strengthen application security practices across Upstart.

• 5+ years of experience in security engineering, software engineering, or a related technical role,…