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

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Founding Engineer (Full Stack)

$150k-$225k + Equity

Neptune is a $7.5M venture-backed startup building a shared AI brain for couples to manage major life decisions. Backed by Floodgate and The General Partnership, Neptune was founded by product and engineering leaders from Google, Stripe, and Uber to simplify complex financial and legal workflows through emotionally intelligent technology.

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.

New York, USA

• 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.

• 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.

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