Kastle
YC S24 startup building AI voice agents for mortgage servicing: payments, escrow, loss mitigation. Founded 2024, SF, team of 10, $2.8M raised. Hiring, but roles are SF in-person, not remote.
What is Kastle?
Kastle builds AI voice and messaging agents for consumer lending, starting with mortgage servicing. Its agents handle borrower interactions across voice, SMS, email, and chat: collecting payments, answering escrow and loan questions, working loss mitigation, and supporting compliance monitoring, which lets a lender service borrowers around the clock without scaling a call centre in proportion. The company reports roughly 70 percent lower cost per call, 40 percent lower handle time, and CSAT above 90 percent. Kastle was founded in 2024 and went through Y Combinator's S24 batch. Its co-founders are Rishi Choudhary, who is CEO and previously led Redfin's Mortgage Marketplace team as a product manager, where he saw that traditional lenders lacked the infrastructure to service online inquiries, and Nitish Poddar, who is CTO and was previously a tech lead at Verkada. The company is based in San Francisco with a team of around 10 people, and has raised roughly $2.8 million across two rounds: a $125,000 Y Combinator seed in July 2024 and a $2.3 million round in March 2025, backed by Commerce Ventures alongside Y Combinator and angels from Snapdocs, Google, and WePay. Its commercial traction is documented in mortgage trade press: partnerships with the servicing fintech Haven in October 2024, with New American Funding, and with Carrington Mortgage Services, whose roughly $200 billion servicing portfolio saw Kastle's agents deployed across its contact centre and borrower-facing operations in July 2026. It also won LendingTree's 2024 Innovation Challenge for AI voice technology in mortgage servicing. Note for remote job seekers: Kastle is hiring, but its roles are San Francisco based and in person.
Mission & values
Give every borrower an immediate, accurate answer about their loan, by building the AI operating system for consumer lending.
Qualifications
Kastle is a small, early-stage, engineering-heavy team of around ten people, so roles carry wide scope. Its recently listed openings give a clear picture of what it wants. A Forward Deployed Engineer at $170,000 to $250,000, explicitly open to new graduates, working directly with lender customers to implement and tune the AI agents in their environment, which suits someone comfortable splitting time between writing code and sitting with a customer. A Staff Engineer at $250,000 to $320,000 requiring eight or more years of experience, for someone who can own core architecture at a company operating in a regulated financial domain where an incorrect answer to a borrower carries compliance consequences. An Enterprise Account Executive selling into mortgage servicers and lenders, also marked open to new graduates. And a Founder Intern position paying $8,000 to $8,750 monthly. Useful background includes voice AI and LLM application work, mortgage or consumer lending domain knowledge, and experience in regulated financial software. Two things to be clear about before applying. Every one of these roles is based in San Francisco with no remote option indicated, so this is in-person work rather than a remote opportunity, which matters if you found this listing on a remote jobs board. On the positive side, Kastle publishes salary bands upfront on its engineering roles, which is not universal even among Y Combinator companies and lets you judge the offer before investing time.
Leadership
Rishi Choudhary
Co-Founder & Chief Executive Officer
Co-founded Kastle in 2024 after leading Redfin's Mortgage Marketplace team as a product manager, where he saw that traditional lenders lacked the infrastructure to service online borrower inquiries.
Nitish Poddar
Co-Founder & Chief Technology Officer
Co-founded Kastle in 2024 and leads its engineering, having previously worked as a tech lead at the security technology company Verkada.
Hiring process
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1
Apply via the Y Combinator jobs board
Kastle lists its openings through YC. Note every role is San Francisco based and in person, with no remote option indicated.
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2
Founder screen
At a team of roughly ten, expect to speak with a co-founder early. Confirms fit, level, and that you are able to work in person in San Francisco.
About 5 days
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3
Technical or role interview
Engineering: coding plus system design, likely touching voice AI and LLM application work. Account executive: a sales scenario selling into mortgage servicers.
About 7 days
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4
Work sample or onsite
Early-stage startups commonly use a practical exercise or paid work trial. Forward-deployed roles may probe how you handle direct customer implementation work.
About 7 days
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5
Offer
Offer against the published band for the role, with equity typical at seed stage. Clarify the equity component, since only cash bands are published.
About 5 days
Funding
Awards & recognition
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Won LendingTree's Innovation Challenge for AI voice in mortgage servicing · 2024
LendingTree
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Deployed across Carrington Mortgage Services' ~$200B servicing portfolio · 2026
National Mortgage News
Company information
- Industry: AI Voice Agents / Mortgage & Consumer Lending Tech
- Location: San Francisco, CA, USA (roles are in-person, not remote)
- Founded: 2024
- Employees: 10
- Website: www.kastle.ai ↗
- LinkedIn: Company page ↗