Posted on:June 3, 2026

Software Engineer, Security at Lassie

Lassie is hiring a Software Engineer, Security in San Francisco, CA, US. On-site.

About Lassie

Lassie is an AI assistant that automates administrative tasks for doctors' offices, including insurance enrollments, payment posting, and EFT reconciliation. It handles paperwork such as setting up electronic payments, matching payments to insurers, patients, and claims, and recording payments in the practice management system.

Software Engineer, Security job description

Our mission is to help small businesses run themselves. We’re starting with doctors’ offices, building autonomous systems that handle busywork and complete the workflows that keep the office moving every day. Our team is small, flat, and ambitious. We value craft, intellectual rigor, and direct communication.

About the role

Security engineers make Lassie trustworthy enough to operate inside critical office workflows. You’ll build the controls, systems, and engineering practices that protect customer data while letting an ambitious team move quickly.

What you'll do

  • Build core security systems across access control, audit logs, data protection, monitoring, and incident readiness

  • Partner with engineering to threat-model new agent workflows and make security part of how we build

  • Help Lassie move quickly while earning the trust required to operate inside critical office systems

Some things we've built

  • Data pipelines processing $1B+ in insurance claims

  • Systems that eliminate thousands of hours of paperwork every month

  • A sync engine backed by encrypted SQLite in the browser, enabling 100ms experiences for healthcare payments and patient ledgers

Technology we use

We invest heavily in productivity. Engineers should have the best tools for the job and the freedom to choose them.

  • Python (Django, Pydantic AI), Postgres, Redis

  • TypeScript, React, Tailwind

  • Google Cloud Platform, Vercel

  • Linear, Slack, Notion

Joining us

To start, you'll have a handful of conversations with our team and founders. If there is mutual excitement, we'll invite you to the office where you'll work on a small project and meet the team.

Apply now

Applications go straight to Lassie. We never sit between you and the employer.

Apply now ↗
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