AI Product Focus - Senior Full Stack / Rails Engineer (Boston)

Responsibilities

Backend Engineering

• Architect, build, and scale large Ruby on Rails applications
• Own major systems within our Rails API, including performance, reliability, and maintainability
• Manage PostgreSQL at scale: schema design, indexing, performance diagnostics
• Maintain and optimize Redis + Sidekiq pipelines for high-throughput workloads
• Lead backend-heavy feature projects, from design to deployment

AI / LLM Systems

• Integrate, evaluate, and iterate on LLM providers and models
• Design systems that manage non-deterministic model outputs safely and predictably
• Build and own A/B tests, eval pipelines, and agentic workflows
• Optimize for latency, reliability, and cost across LLM-heavy features
• Contribute directly to prompts, agents, and AI system architecture

Product & Full-Stack Contribution

• Collaborate tightly with founders and engineers to define product requirements
• Jump into frontend (Next.js/React) when needed to ship features end-to-end
• Run rapid product iterations: fast feedback loops, experimentation, data-driven decisions
• Maintain a high bar for product quality while optimizing for speed of execution

Requirements

• 5–10+ years of experience building and scaling production Rails applications
• Expert-level Ruby on Rails knowledge: ship quickly and safely
• Pragmatic: make thoughtful trade-offs that maximize user value and iteration speed
• Take ownership and thrive in high-velocity environments
• Recent, hands-on experience with LLMs and use AI in day-to-day workflow
• Comfortable navigating ambiguity, experimenting, and working with non-deterministic systems
• Able to contribute across the stack (backend-first, but not backend-only)
• Deeply care about product quality, speed, and delivering great user experience