Founding Applied AI Engineer at Kastle About Kastle Kastle is an AI platform serving America’s largest mortgage lenders, helping them collect payments, resolve disputes, and streamline loan processing. Backed by $2.3M from Y Combinator, Commerce Ventures, and executives from Snapdocs, Google, and WePay, we’re redefining loan servicing with AI. About the Role As a Founding Applied AI Engineer, you will play a crucial role in integrating advanced AI technologies into Kastle’s platform. You’ll work on fine-tuning large language models (LLMs), designing AI workflows for highly regulated enterprises, and ensuring our AI agents deliver precise, compliant, and effective interactions. This role is ideal for an engineer who is passionate about applied AI, eager to solve real-world challenges, and excited to build the technical foundation of an early-stage AI startup. Responsibilities AI Model Integration: Fine-tune and deploy LLMs for real-time borrower interactions. Prompt Engineering: Design, test, and iterate on prompts to optimize AI performance and compliance. Custom AI Solutions: Train and implement domain-specific AI models for mortgage servicing. Scalability & Compliance: Ensure AI solutions meet regulatory standards (FDCPA, RESPA, TILA) and scale efficiently. Data Pipelines & APIs: Build robust AI-driven workflows that integrate seamlessly with loan servicing platforms. Continuous Optimization: Monitor AI performance, reduce error rates, and enhance borrower experience. What We’re Looking For 3+ years in applied AI, ML engineering, or a related role. Proficiency in Python, TensorFlow/PyTorch, and deep learning frameworks. Experience fine-tuning LLMs (Llama, GPT) and designing AI prompt workflows. Strong product mindset—ability to bridge AI capabilities with real-world mortgage servicing needs. Understanding of mortgage regulations (or willingness to learn) to ensure AI compliance. Experience with deploying AI models into production and optimizing for speed and accuracy. Strong communication skills to collaborate with product, engineering, and compliance teams. Why Join Kastle? Be part of a fast-growing AI startup shaping the future of financial services. Work on cutting-edge AI technologies solving high-impact problems. Collaborate with a top-tier team backed by leading investors. Competitive salary, early-stage equity, and ownership over AI strategy. Ready to Build AI for the Future of Mortgage Servicing? If you’re excited to push the boundaries of applied AI and help scale a category-defining company, we’d love to hear from you. Apply now to join Kastle as a Founding Applied AI Engineer.