Founding Engineer - Abacus

About Abacus Abacus is reinventing how accounting firms operate by building AI agents that automate the tedious, repetitive workflows that teams currently face. Our core engine combines advanced OCR and LLMs to deliver truly intelligent back-office automation. We're already working with large enterprise clients, generating meaningful revenue, and backed by top-tier investors. We’ve accomplished all of this as a team of two, and we’re excited to grow our team. If you want to shape the future of AI-powered operations and own meaningful technical work from day one, this is the place. The Role We're hiring our first Founding Engineer to own and expand the core machine learning engine behind Abacus. You’ll report directly to the co-founders and work in person from our SF office. This is a rare opportunity to join a high-growth company as an early engineer with massive autonomy and influence over product and technical direction. In your first 3–6 months, you’ll: Improve and scale our ML extraction engine using LLMs and OCR Own backend architecture and infrastructure decisions Build and ship greenfield features to expand the workflows we automate Over the next year, you'll help lay the groundwork for our engineering org as we scale, while staying hands-on and focused on impact. What You’ll Do Lead development of our ML-powered document extraction engine Architect backend systems with performance and scalability in mind Build and deploy new automation features for tax firms Collaborate closely with the founders on product and user needs Help define our engineering culture and technical roadmap What We're Looking For Must-haves: 1–5 years of experience, ideally in high-ownership or early-stage environments Strong backend development skills, particularly in Python Proven 0→1 builder (side projects, startup experience, or both) Willingness to work from our SF office, 5 days/week Willingness to complete a technical take-home exercise as part of the process Nice-to-haves: Experience with LLMs, OCR, or data extraction systems Exposure to AI infrastructure or evaluation frameworks Why Join Us No ceiling on ownership or growth Significant equity and high-leverage role at a fast-growing startup Top-tier health insurance, daily lunches, and an in-office barista You’ll help define the trajectory of the product, team, and company!