Senior Product Engineer

Fine Tune builds platforms that help large enterprises manage complex indirect spend. The Senior Product Engineer owns software projects end to end, designs and delivers solutions across the company's web stack, and mentors engineers while helping improve its AI-assisted development workflow.

Responsibilities:

• Own projects from problem definition through delivery and ongoing maintenance, including problems that start ambiguous or loosely defined
• Compare viable approaches and recommend one with clear reasoning
• Cut scope to fit the time available, and know when to cut and when to escalate
• Produce clean, well-tested implementations across Rails and JavaScript/TypeScript; design data models and APIs other engineers build on
• Design systems within our architecture — decompose problems into components with clear responsibilities, boundaries, and interfaces
• Design for failure as well as for the happy path
• Weigh tradeoffs and make the reasoning behind consequential decisions clear
• Debug complex, cross-cutting issues systematically and get to root cause
• Use AI coding agents as a core part of how you deliver: decompose work into well-defined specs and plans, direct implementation, and iterate on the results
• Own every line that ships, whoever or whatever wrote it. Understand it well enough to explain it, predict its behavior, and change it
• Review AI-generated code with deliberate thoroughness for correctness, security, and fit with our architecture
• Help improve our AI development workflow, including the context, conventions, and automated gates that make agent output reliable
• Choose the right verification strategy for the work and verify behavior against intent, not just against the implementation
• Apply established security patterns and handle sensitive client data appropriately
• Spot security risk before it ships
• Mentor engineers; give thoughtful code reviews that raise the team's bar by example with well designed and scalable architecture
• Evaluate implementations you didn't write for correctness, security, and fit
• Drive technical decisions and build consensus across the team without relying on authority
• Identify and lead improvements to code, architecture, testing, and process
• Partner with product and QA to turn business needs into well-scoped work delivered iteratively
• Work in fixed cycles with a small team that owns shaped work end to end
• Communicate decisions, tradeoffs, progress, and risks clearly across the team
• Contribute to architecture and design discussions and to team learning initiatives like book clubs and mentoring

Requirements:

• Candidates must be US citizens
• 5+ years of professional product or software engineering experience, or equivalent demonstrated ability
• Strong proficiency in modern web development languages (Ruby and JavaScript/TypeScript preferred) and full-stack frameworks (Rails, React, or similar)
• Independently produces clean, tested implementations and debugs complex issues systematically
• Designs systems within an existing architecture and applies patterns appropriately
• Designs efficient data models, optimizes queries and indexes, and implements security measures
• Comfortable with Git, CI/CD pipelines, infrastructure as code, and modern development tooling
• Hands-on experience building production software with AI coding tools (Claude Code, Cursor, Copilot, or similar), and a clear point of view on where they help, where they don't, and how you verify their output
• Demonstrated ability to own a project end to end, from problem definition to production
• Deep understanding of the business your software serves, or a clear track record of building that understanding quickly
• Comfortable reasoning about the why behind a requirement, not just the what
• Strong communicator — you present complex technical information clearly and facilitate productive discussions
• Collaborative and empathetic — you drive cross-team collaboration and build strong working relationships
• Creative problem solver — you solve novel problems and make sound decisions with incomplete information
• Ownership mindset — you take ownership beyond your immediate role and drive initiatives to completion
• A leader without authority — you influence significant technical decisions and mentor others as they grow
• Organized and adaptable — you balance priorities, estimate accurately, and adapt as requirements change
• Experience with Ruby on Rails specifically, including Hotwire and Stimulus
• Familiarity with cloud platforms and managed platforms (Railway, Heroku, Azure, AWS, or comparable) and containerization (Docker)
• Microsoft integrations (Entra, Dynamics 365, SharePoint)
• Understanding of API design (REST, GraphQL) and architectural patterns
• Exposure to enterprise software, procurement, or expense management domains