Staff Engineer.

About Kastle

Kastle is building the AI employee for consumer lending. We work with some of America's largest banks and mortgage lenders, helping them scale their contact center and compliance operations using autonomous AI Agents that process payments, originate loans, and help customers get a world class experience during the biggest financial decisions of their lives. We've processed over $1 billion in transactions and are backed by Y Combinator and Commerce Ventures. If you are interested in building AI that is applied in the real world where precision, reliability, and performance matter and redefine access to credit across the world, apply below.

What You’ll Do

• Architect and own core systems that power real-time AI voice and compliance workflows

• Push performance boundaries, delivering sub-700ms latency leveraging event driven architecture and parallel processing

• Deploy, operate, scale, resilient systems using Kubernetes and distributed sub-systems

• Build a self-improving AI system that improves with every customer interaction and human feedback

• Ship fast, ship right from whiteboard design to live production in bank environments.

What You Bring

• Strong fundamentals in building high-performance, real-time backend systems (we work primarily in Python).

• Deep understanding of distributed systems, reliability, and fault tolerance.

• Excellent database design and performance optimization skills.

• A bias for ownership and an ability to figure things out in messy, high-velocity environments

Nice to Have

• Experience with training, designing, or building production AI/ML systems

• Previous startup or founder experience.

The Interview Process

We respect your time. Our process is short and designed to let you showcase how you think:

1. 15-min call with Talent Lead to learn more about the role

2. 1-hour live coding session with Founding Engineer

3. 1-day onsite with team

Why join Kastle

• Opportunity to work with a world class team building a generational AI company that will redefine how every loan in America is made and managed

• Ability to move fast while your work impacting millions of customers. Add a new feature in a few days and ship it to top 10 lenders the next week.

• Competitive Compensation + Meaningful Equity at a high growth company

• High ownership and direct input on product direction, company culture, and how the FDE function scales

Other Perks and Benefits

• Free gym membership

• Robust medical, vision, & dental coverage

• 401(K) plan offering

• Paid Company Meals

• Company offsites to get to know the team