Staff Engineer

About the Company

Kastle is building the AI operating system for consumer lending. We partner with some of America’s largest mortgage lenders to transform their contact centers and compliance operations with AI voice agents. Backed by Y Combinator, Commerce Ventures, and executives from Snapdocs, Google, and WePay, we’re redefining how millions of borrowers interact with financial institutions.

Responsibilities

• 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

Requirements

• Strong fundamentals in building high-performance, real-time backend systems (primarily Python)
• Deep understanding of distributed systems, reliability, and fault tolerance
• Excellent database design and performance optimization skills
• A bias for ownership and ability to navigate high-velocity environments

Preferred Qualifications

• Experience with training, designing, or building production AI/ML systems
• Previous startup or founder experience