We're looking for a Founding Engineer to join as one of the first three engineering hires at a pre-seed AI startup in San Francisco. You'll build an operating system that runs service businesses with a workforce of AI agents, starting from nothing, and you'll own large parts of the product, architecture and infrastructure yourself. This is a CTO-calibre seat with meaningful equity. It suits someone who has already built something from nothing to production as a founder, co-founder, CTO or very early engineer. Depending on your strengths, you'll lean toward product and design-minded engineering, agent and LLM engineering, or full-stack, infra and scaling work, and in practice you'll touch all three. You'll work directly with a second-time founder who has a prior exit. There are no management layers and no backlog of tickets handed down to you. The role is fully on-site in SF, six days a week, so it's built for people who want to go all in at the earliest stage of a company.

Details:
Schedule: Full time
Location: San Francisco, CA (Onsite, 6 days a week)
Start: ASAP (a staged start is possible, e.g. a month in Vienna before moving to SF)
Duration: Long-term
English: Fluent
Type of collaboration: Internal Employment

About the project:
The company is building infrastructure for AI-native service companies: an operating system where AI agents run service-business operations end to end. It is led by a serial founder whose previous company exited and who recently moved to San Francisco to build this one. The company has just closed a strong angel round from well-known European and US angels. It is extremely early, and the first engineers will set the product direction, technical architecture and engineering culture. The team works fast, in person and with a high bar, and uses agentic tooling as part of everyday work. Relocation to SF is supported, including O-1 visa sponsorship for strong international candidates. Equity runs from 1 to 3%, and co-founder-level equity is possible for exceptional people.

You have:

2 years of real full-time, hands-on engineering experience
Zero-to-one experience: founder, technical co-founder or CTO of a real startup, or a founding or very early engineer (roughly the first 20 people) at a high-growth startup
A track record of personally building production-grade systems, not only research or prototypes
Strong skills in TypeScript and/or Python, with experience in full-stack development and distributed systems
Hands-on experience with LLMs and AI agents, including evals
Daily use of agentic tooling, ideally including harnesses or tools you've built for yourself, plus side projects
At least one standout signal: early at a strong AI-native or YC startup, a top internship (quant firm, AI lab or top tech), olympiad results, a hard side project, or a strong school
Based in San Francisco or willing to relocate, and genuinely up for six days a week in person
US work authorisation, or a profile that could support an O-1 visa (awards, publications, press or a founder track record)
A stable track record without a pattern of short stints, and a preference for full-time employment over freelance or contract work

What to do:

Build the core product from scratch as one of the first engineers, from architecture through shipped features
Design, build and scale the AI agents and LLM systems that run service-business operations end to end
Build and own evals that measure and improve how well and how reliably the agents work
Own full-stack work across frontend, backend and infrastructure, and make core technical decisions with little oversight
Turn unclear problems into working software quickly, and work with the founder on product direction
Build internal agentic tooling that makes the team faster
Help shape the engineering culture, hiring bar and practices as the team grows

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