Founding Product Engineer

Arceus•San Francisco, CA

10d•$140,000 - $180,000•Onsite

About The Position

Arceus is building an AI-native law firm for the next generation of category-defining companies. It helps fast-moving companies move contracts through legal with speed, transparency, predictable pricing, and exceptional quality. The Founding Product Engineer will build the platform that is reinventing how legal work gets done, working closely with attorneys and AI engineers to turn legal judgment into software. This is an in-person role based in San Francisco. The engineer will build and own core product features across the stack, collaborate on converting legal workflows and review playbooks into reliable software, and make pragmatic decisions about architecture and tooling. They will own the quality and reliability of production software, help establish engineering culture and standards, and prioritize customer experience. The role offers the opportunity to shape a growing company and engineering team, take on substantial responsibility, and grow professionally. The company expects urgency, ownership, consistent execution, and a high standard of work.

Requirements

1–3 years building and shipping production software, ideally at an early-stage company, or experience as a founder.
Willingness to work 12 or more hours per day, 6 days per week, including weekends.
Ability to thrive in an exceptionally high-bar environment where employees are expected to go above and beyond.
Strong product instincts and full-stack ability, such as TypeScript/React on the front end, a modern backend stack, and relational databases.
Experience building something with AI/LLMs, at work or independently.
Track record of owning features end to end and making sound engineering trade-offs.
Comfort with ambiguity and experience in a fast-moving, high-ownership environment.
Excellent judgment and communication, and a high bar for personal work.
Relentless, urgent, resilient, and persistent approach to delivering results.

Responsibilities

Build and own core product features across the stack, from data models to the interfaces attorneys and clients use.
Partner with AI engineers and attorneys to turn legal workflows and review playbooks into reliable software.
Make pragmatic architecture and tooling decisions that support speed while avoiding future limitations.
Write maintainable code, build for reliability, and take responsibility for production work.
Help define engineering culture and standards, and contribute to hiring as the team grows.
Move work over the finish line while prioritizing the customer experience.
Own features end to end and make sound engineering trade-offs.