Software Engineer, Applied AI

About the role

About Mantle

We’re building an AI agent to help families support their aging parents (origin story here).

Over 40M “sandwich generation” Americans currently manage their parent’s affairs. Keeping mom/dad safe and supported is like a second job: it’s time-consuming, stressful and on top of their already busy lives. We believe that managing our parents’ affairs should feel under control, easier and lower stress.

Co-founded by serial entrepreneur partners including Ted Zagat, who sold his previous businesses to Slack (announcement here) and Google (Zagat restaurant guides).

The Role

This position is core to our product. Mantle is an AI agent, so the quality, reliability and trustworthiness of that agent is the product. As a Software Engineer on our Applied AI team, you'll design and build the agent systems that take real work off of families' plates: understanding their situation, taking action on their behalf, and knowing when a human needs to step in.

You'll work directly with founders and the engineering team to take agent capabilities from prototype to production. It's not just about clever prompts; it's about the unglamorous work of building evals, chasing down failure cases, and making the agent dependable enough that families can rely on it every day.

What You'll Build

Agent orchestration: The core systems that let Mantle's agent plan, use tools, remember context and complete multi-step tasks for families

Evaluation frameworks that measure quality, accuracy and safety, and catch regressions before our users do

Guardrails and escalation paths that keep the agent trustworthy with sensitive personal and financial information

Retrieval and memory systems that give the agent the right context about each family at the right time

Integration layers connecting AI models, third-party services and internal systems into cohesive user experiences

Feedback loops and data pipelines that make the agent better every week

What We're Looking For

Required Experience

2-10 years building production software with modern technologies

Hands-on experience shipping LLM-powered features or agents to real users

Strong grasp of prompt design, retrieval, tool calling and agent orchestration patterns

Experience building evaluation systems and using them to drive product decisions

Strong backend skills (e.g. Python or Node.js, APIs, data pipelines) and experience deploying on AWS

Ideal Background

Early-stage startup experience (especially as a first-10 engineer)

Experience building multi-step agents that take real actions on a user's behalf

Experience designing AI systems that handle sensitive personal or financial information

Understanding of product development and what makes AI feel trustworthy to everyday consumers

Nice to have, but not required: experience with FinTech

Who Thrives Here

Builders: You love creating things from scratch and taking full ownership

Rigorous: You measure quality instead of assuming it

Product-minded: You think about user impact, not just technical elegance

AI-forward: You stay on the frontier of models, tools and techniques, and use AI development tools (Cursor, Claude Code, etc.) every day

Pragmatic: You balance perfection with speed and know when to ship

Autonomous: You thrive with minimal direction and maximum responsibility

Mission-driven: You care about building something meaningful

What You'll Get

Meaningful work: Build an AI agent that will improve the lives of millions of families, with real technical ownership, fast pace, and huge financial potential

Small team impact: Work directly with founders and see immediate impact from your work

Early team equity: Meaningful ownership in a company targeting a massive market

Shape the future: You will own the core of our product; your decisions will shape how Mantle's agent thinks and acts

Learning & growth: Work on some of the hardest open problems in applied AI

Remote Fridays: Work from home every Friday. Monday through Thursday, we build together in person in San Francisco