Senior Product Engineer

About Fine Tune Fine Tune helps large enterprises bring complex indirect services under control, specializing in facilities management, uniform rental, waste and recycling, security and guard services, pest control, and energy and utilities. We combine experienced operators with our auditing platform, eMOAT℠, to monitor invoices and enforce agreements month after month, providing spend confidence to our clients in procurement and finance. The world’s most recognizable brands choose Fine Tune, including Cargill, Caterpillar, Valvoline, Pfizer, Tyson Foods, and American Cancer Society. For more information, visit www.FineTuneUS.com. The Opportunity We're looking for a Senior Product Engineer who owns problems end to end — from an ambiguous idea through a shipped, maintained solution — and lifts the engineers around them while doing it. You'll join a collaborative team building the platforms that help some of the world's largest companies manage complex indirect spend. This role is defined by ownership of outcomes. You'll take direction on what needs solving, but you'll own how it gets solved: shaping the approach, deciding what ships within the time available, making sound design decisions, and seeing the work all the way into production. Working across our Ruby on Rails and JavaScript/TypeScript stack, you'll be a technical example for the team — mentoring engineers, raising the quality bar, and helping shape how we build. We build with AI at the center of our workflow. You'll work alongside AI coding agents every day: shaping problems and writing specs and plans they can execute against, then reviewing and verifying what they produce. The judgment you bring to design, scope, and correctness matters more here, not less. You'll also be expected to learn our business deeply. Our clients are procurement and finance teams at major global companies, and the best decisions here come from understanding why their world works the way it does. At Fine Tune, our core values of honesty, dedication, and vigilance foster an environment of trust, open communication, and inclusivity where everyone can do their best work. If you care about your craft, want to keep getting better, and thrive in a team that's building something meaningful — let's talk. This is a full-time, salaried, remote position. Candidates must be US citizens and located in the United States. What You'll Do Own Problems & Deliver 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 & Decide 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 Build with AI 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 Verify & Protect 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 Lead & Mentor 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 Collaborate & Grow 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 What We're Looking For Craft 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 Domain 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 Professional Skills 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 Nice to Have 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 Why Join Growth Path: We invest in your development with clear career progression, regular feedback cycles, and a rubric-based framework so you always know where you stand and where you're headed Learning Culture: Book clubs, mentoring programs, and a team that values continuous improvement — we believe in "Learn One, Do One, Teach One" AI-Native Engineering: We've rebuilt how our team works around AI-assisted development, with real investment in the workflow, tooling, and guardrails, so you'll spend your time on the parts of the job that need an engineer Collaborative Team: Work with a tight-knit engineering team that values quality, open communication, and professional growth in an inclusive environment Meaningful Impact: Your work directly helps remove the tedious, complex work that bogs down procurement and finance teams at major global companies Healthy Balance: Remote flexibility with respect for work-life balance — we believe sustainable work leads to better outcomes The Pay Range For This Role Is 130,000 - 160,000 USD per year(Remote (United States))