Senior Full Stack Engineer / Ruby on Rails / Union Square, NYC

A mission-driven startup operating at the intersection of climate and fintech is seeking a Senior Full-Stack Engineer to help build products that make sustainable building upgrades—such as heat pumps, batteries, and EV chargers—more accessible through innovative financing. This is a hybrid role based in New York City, with flexibility on level from Senior to Principal.

What You’ll Do

• Own end-to-end feature development, from ideation and architecture through deployment
• Write and review code across the full stack while balancing speed and quality
• Shape technical architecture, best practices, and decisions around technical debt and build-vs-buy
• Partner closely with founders and product stakeholders to influence roadmap and priorities
• Work cross-functionally and gain exposure to multiple areas of the business, including sales and customer discovery

• 5+ years of experience with Ruby on Rails or similar full-stack frameworks
• Strong understanding of modern web application development
• Deep experience with database design and management
• Excellent communication skills and comfort working across product and technical teams
• Ownership mindset and ability to thrive in ambiguity
• Experience building systems from 0?1 and scaling them
• Experience or strong interest in AI, ML, and LLMs

• $160,000–$200,000 base salary (NYC) plus competitive equity
• Health, dental, and vision coverage
• Unlimited PTO
• Opportunity to join early and make a meaningful impact at a fast-growing, mission-oriented startup in climate and fintech