Founding Engineer

We are looking for a Founding Engineer with 2-6 years of experience to help build the AI agents that automate tax preparation for the largest accounting firms in the US. Abacus is profitable, has passed seven figures in revenue in under a year, and is live in 11 of the top 100 firms. We want a high-bar generalist who makes sharp backend decisions and wants to help scale a product that customers already pay for.

What will you be doing?

• Build the core tax-automation platform as a generalist: mostly backend, with some frontend
• Help ship the next major version of the product, a big relaunch planned for early next year
• Make backend architecture decisions on your own, working closely with the CTO and Head of Engineering
• Build our LLM and OCR agent pipelines and turn what firms tell us into product
• Work on new products in tax and in other accounting workflows, such as audit

Key Requirements

• Strong Python skills; TypeScript is a strong plus
• Hands-on experience making backend architecture decisions
• Experience at a venture-backed, fast-growing startup (Seed through Series B) is strongly preferred; long tenures at big tech or slow enterprises are a negative signal
• CS degree strongly preferred (Math or Physics also considered) from a top-50 US school, ideally with a strong GPA
• A builder mindset with high ownership and urgency; side projects and 0-to-1 work are a plus