---
title: 'Staff AI Engineer at Kastle'
canonical: 'https://feeny.ai/job/staff-ai-engineer-kastle-san-francisco-pd6as3jgcxct'
type: 'job'
last_seen: '2026-09-05'
---

# Staff AI Engineer at Kastle

- **Company:** Kastle
- **Location:** San Francisco, CA
- **Compensation:** $250k–$350k
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2025-11-22
- **Last confirmed live:** 2026-09-05
- **Apply:** https://jobs.ashbyhq.com/kastle/e80efb99-7c18-4af1-a591-c082528bf6b9

## Job description

## 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.

## ABOUT THE ROLE

As a Founding Applied AI Engineer, you'll be instrumental in building the technical foundation of Kastle's AI platform. You'll fine-tune large language models, design AI workflows for highly regulated enterprises, and ensure our voice agents deliver precise, compliant, and effective borrower 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.

## WHAT YOU'LL DO

- AI Model Integration: Fine-tune and deploy LLMs for real-time voice-based borrower interactions
- Prompt Engineering: Design and iterate on prompt strategies to optimize AI performance and compliance
- Evaluate LLMs and AI Agents: Build high quality evals using our proprietary datasets to benchmark AI agent performance and run experiments
- Custom AI Solutions: Train and implement domain-specific AI models for consumer lending
- 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 performance metrics and continuously improve agent quality and borrower experience

## WHAT WE'RE LOOKING FOR

- 3+ years building and deploying ML/AI systems in production environments
- Strong proficiency in Python and deep learning frameworks (TensorFlow, PyTorch)
- Experience with LLM orchestration frameworks (LangChain, LlamaIndex, or similar)
- Track record of shipping end to end AI systems that is at the core of company operations
- Strong product mindset and ability to translate business requirements into AI solutions
- Excellent communication skills to collaborate across product, engineering, and compliance teams

## 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 Health and Wellness Membership
- Robust medical, vision, & dental coverage
- 401(K) plan offering
- Paid Company Meals
- Company offsites to get to know the team

## About Kastle

## Core Business
- **Primary industry**: Consumer lending / Mortgage servicing technology (Fintech)
- **Target customers**: FDIC-insured banks, independent mortgage banks (IMBs), and large consumer lenders (B2B, Enterprise)
- **Mission or purpose statement**: To help traditional financial services companies better interface with their customers by automating high-volume phone calls with compliant AI agents.

## Products & Services
- **Avery (Servicing Agent)**: AI voice agent that handles borrower inquiries, payment collection, escrow questions, and loss mitigation. Integrates with ICE’s MSP system.
- **Collections Agent**: Automates payment reminders, engages delinquent borrowers early, and recovers past-due accounts.
- **Compliance Agent**: Monitors and scores every interaction against regulations (FDCPA, TILA, UDAAP, RESPA, TCPA) for 100% QA coverage.
- **Loan Officer Assistant**: Qualifies new loan inquiries and automates pre-qualification calls.
- **Sentinel (QA & Compliance Agent)**: Real-time monitoring and automated scorecards for borrower calls and servicing documentation.
- **Agent Builder**: Allows lenders to turn SOPs into AI agents using natural language, with no-code configuration.
- **Platform features**: Omnichannel support (voice, SMS, email, chat), simulation testing, transparent observability, and integration with existing contact center, payment processor, and LMS systems.

## Market Standing
- **Valuation**: Not disclosed (private startup)
- **Key Metric**: Total funding of $510,000 (Pre-seed round led by Y Combinator, June 2024)
- **Notable Investors/Partners**: Y Combinator (lead), ICE Mortgage Technology (integration partner)
- **Growth Signals**:
  - Headcount: 10 employees (+66.7% YoY)
  - Won LendingTree’s 2024 Innovation Challenge (Nov 2024)
  - Featured in a16z’s February 2025 fintech newsletter on voice AI
  - Integration with ICE’s MSP servicing system (April 2026)
  - Most deployed AI voice agents in the mortgage industry (per website)
  - Active job postings: 8 positions, with 300% yearly increase in listings

## Competitive Advantages
- **Purpose-built for compliance**: Pre-trained on key lending regulations (FDCPA, TILA, UDAAP, RESPA, TCPA) with a proprietary Compliance Engine.
- **Enterprise-grade integrations**: Direct connectivity with ICE’s MSP (the dominant mortgage servicing system) and other core systems.
- **Fast time to value**: Go-live in days with out-of-the-box agents that map to existing workflows.
- **Transparent AI**: All responses are fully explainable with built-in reasoning, enabling audit-ready operations.
- **Battle-tested track record**: Claims to have the most deployed AI voice agents in the mortgage industry, with proven metrics (70% lower cost per call, 40% lower handle time, 90%+ CSAT).

## Strategic Focus
- Deepening integrations with core mortgage systems (e.g., MSP) to reduce friction for large lenders.
- Scaling the AI agent workforce across the full lending lifecycle (origination, servicing, collections, compliance).
- Expanding from voice to true omnichannel (SMS, email, chat) and adding more pre-built agent types.
- Growing the enterprise customer base among FDIC-insured banks and IMBs.

## Why Work Here
- **Culture**: Early-stage YC startup with a small, high-agency team (10 people). Founders have strong product/engineering backgrounds (Redfin, Verkada). Emphasis on building mission-critical AI for a regulated industry.
- **Work policy**: Based in San Francisco (185 Channel Street). Likely in-office given the early stage and need for close collaboration.
- **Notable perks/engineering culture**: Opportunity to work on proprietary inference technology, compliance engine, and real-time AI systems. Roles span applied AI, forward deployment, and product management. High ownership and impact from day one.
- **Growth trajectory**: Rapid headcount growth (66% YoY), multiple open roles, and strong market traction suggest significant career growth potential.

## Sources
1. [kastle.ai](https://www.kastle.ai/)
2. [ycombinator.com](https://www.ycombinator.com/companies/kastle)
3. [linkedin.com](https://www.linkedin.com/company/kastleai)
4. [cbinsights.com](https://www.cbinsights.com/company/kastle)
5. [ycombinator.com/jobs](https://www.ycombinator.com/companies/kastle/jobs)

## Other roles at Kastle

- [Head of Sales](https://feeny.ai/job/head-of-sales-kastle-san-francisco-d0xkyqh7a74w) — San Francisco, CA
- [Software Engineer - Intern](https://feeny.ai/job/software-engineer-intern-kastle-san-francisco-25ekajcm3kk7) — San Francisco, CA
- [Senior Product Manager](https://feeny.ai/job/senior-product-manager-kastle-san-francisco-w8f083jn8y91) — San Francisco, CA
- [AI Deployments Lead](https://feeny.ai/job/ai-deployments-lead-kastle-san-francisco-dk0d9gy0kw3b) — San Francisco, CA
- [Mortgage Originations Process Specialist](https://feeny.ai/job/mortgage-originations-process-specialist-kastle-san-francisco-cpcar50m80p4) — San Francisco, CA
- [Founder's Office](https://feeny.ai/job/founder-s-office-kastle-san-francisco-cfysxyhxtfnp) — San Francisco, CA
- [AI Trainer (Part-time)](https://feeny.ai/job/ai-trainer-part-time-kastle-remote-gawt2gvp2g56)
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- [Enterprise Account Executive](https://feeny.ai/job/enterprise-account-executive-kastle-san-francisco-h9mz7tqdf5ww) — San Francisco, CA
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