Founding Engineer (Full Stack) ($150k-$225k + Equity) at Neptune

About the role

As Neptune's first founding engineer, you will architect and build the core AI engine and product experience from the ground up. You'll work alongside world-class founders to turn emotionally charged financial decisions into seamless, trust-based workflows. This high-impact role involves setting the technical foundation while shipping features that directly influence how couples build wealth.

Why this role is remarkable

• Join a world-class founding team including the creator of Google Forms and the founding engineer of Stripe Link.
• Build a category-defining product backed by $7.5M from top-tier investors like Floodgate (early backers of Lyft, X, and Twitch).
• Gain massive ownership and founding-level equity while working with cutting-edge LLMs on high-trust, real-world financial and legal use cases.

What you will do

• Design and ship the "Neptune brain," a shared context engine that manages a couple's full financial and legal history.
• Develop conversational AI and LLM-powered workflows that translate complex model outputs into high-credibility user experiences.
• Own features end-to-end across the stack, from backend architecture and Plaid integrations to frontend execution in Next.js.

Qualifications

• 4–7 years of full-stack experience with a track record of shipping impactful production features in high-trust environments.
• Deep "AI-native" intuition, using LLMs as force multipliers and understanding their performance across sensitive financial tasks.
• Early-stage startup DNA, characterized by extreme agency, product-thinking, and the ability to thrive in an in-office NYC environment.

Location: New York, USA

Salary: $150k–$225k + Equity