Kastle

Staff Engineer

San Francisco
Salary
$250K - $320K
Level
Staff
Work type
On-site · San Francisco

Not stated in the posting: visa.

Open. First seen 6 November 2026.

About the role

About Kastle

Kastle is building the AI employee for banks. We work with some of America's financial institutions, 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 $2 billion in transactions and are backed by Insight Partners and Y Combinator.

Kastle's standard text

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.

We just raised a $24M Series A and are growing fast!

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:

  • 15-min call with Talent Lead to learn more about the role
  • 1-hour live coding session with Founding Engineer
  • 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

What this role asks for

Standard for software engineering roles

Python

Common in software engineering postings at any company.

92% of this description is written for the role. The rest is Kastle's standard text, folded away below.

Compared with Kastle's other open jobs.

The team: Engineering HIRES STEADILY

This role is one of 10 open in Engineering. 4 were posted in the last 30 days and the oldest in September: a team that hires all year rather than one being built.

WHAT THE TEAM WORKS WITH, ACROSS ITS POSTINGS

Python (10 of 10), Kubernetes (6 of 10), CI/CD (4 of 10), LLM (4 of 10), AWS (2 of 10), Azure (2 of 10), Cassandra (2 of 10)

OTHER ROLES ON THIS TEAM

From the team and dates on Kastle's own job board.

Other openings for this role

2 open postings for this role in San Francisco, first posted 14 March 2026. The company is likely hiring for more than one position. None has been taken down and posted again.

Salary context

25 other open postings titled Staff Engineer state a salary: median USD 195,000 to USD 235,000 a year.

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