About TypeSafe

We’re building prod, not god. TypeSafe is an AI lab pushing frontier model intelligence in a new direction, starting with System One Models. We combine the reasoning of LLMs with the reliability of code, for truly trustworthy AI. Our first model, Jev, launched in September 2026.

While others chase leaderboards, we’re rebuilding the LLM stack from first principles to make models smarter and also dependable enough to run in production. We’re a small, fast team backed by an $870M Series A led by a16z. Made in SF, with love. Come join the frontier.

About the role

As a senior backend engineer, you will join the team responsible for building and maintaining TypeSafe's API platform for inference. These APIs will be user facing, latency sensitive, and have uptime, reliability and backwards compatibility requirements. You'll be wearing many different hats and working across different levels in our inference system, with particular depth in distributed systems and networking. Responsibilities include:

• Define APIs for a new kind of AI inference experience and iterate on the design to ensure they are delightful to use

• Create robust infrastructure for serving inference across multiple cloud providers

• Define abstractions that will serve us moving forward as our billing needs and business logic needs grow

• Work on exposing new model features to users

Our tech stack is primarily Python. We also use TypeScript, Next.js, and Tailwind CSS for frontend, with Kubernetes for orchestration. We empower developers to use any tooling they find helpful for getting their job done, including AI and agents.

We expect that you

• Are responsible, ownership-inclined, and a team player – you believe there is no such thing as "other people's code", and will complain only the normal amount about pager duty

• Have experience designing storage abstractions for scaled backend systems

• Have experience designing resilient systems and improving on-call experience on production systems

• Collaborate well with others on technical and product design, advocating for what you need, and adjusting specs to changing requirements and feedback

• Are mission aligned and excited to go all-in

• Love being part of a team

We are hoping that you

• Have previously built big things

• Have 5+ years of professional software engineering experience (3+ years of infra/backend) with a team with rigorous engineering standards

• Have shipped backend services at scale with continuous delivery and uptime SLAs of at least 3 9s

• Have designed and operated a developer-facing API service

• Have experienced LLMs' capabilities and limitations from implementing them in the past

Life at TypeSafe

We’re a small, flat, close-knit team working to make intelligence dependable enough to become part of everyday software. We work fully in person from our San Francisco office near Embarcadero station. We love what we do and care deeply about the work.

We strive for excellence and craftsmanship and won’t stop until we get there. When the team wins, we all win, and we enjoy collaborating and inspiring each other to grow—as a team and as individuals.

We value emotional honesty, kindness, and bringing your whole self to work. We build machines; we don’t try to be machines.

We want TypeSafe to be the place where you do the most impactful work of your career and help define our future as a company.

We provide

• 100% covered health insurance

• Daily lunch and dinner

• Visa sponsorships

• 401K plans