Head Of Engineering

About Flex

Flex was founded to solve a simple but costly problem: making it easy for health and wellness brands to accept HSA and FSA payments online. For years, only giants like Amazon and Walmart could process these payments at checkout, leaving smaller merchants — and their customers — to deal with frustrating reimbursement paperwork. Our technology verifies product eligibility in real time, handles split payments for eligible and non-eligible items, and can even issue Letters of Medical Necessity during checkout. With $150 billion in annual HSA/FSA spending potential, we're giving brands the tools to unlock new revenue and making it easier for consumers to use the benefits they've earned.
About the Role
As Head of Engineering at Flex, you'll own the technical direction of a company defining a new category in healthcare payments. You'll lead and grow a talented engineering team, set the architectural vision, and ensure we're building systems that are reliable, scalable, and ahead of the market. This is a rare opportunity to partner directly with the founders to shape how we build — not just what we build. You're the person who gets us from where we are to where we're going — building the team, processes, and infrastructure to match our next stage of growth.
What You'll Do

• Lead and grow the engineering team — recruit, mentor, and develop engineers across all levels, building a culture of craft, accountability, and velocity.

• Own the technical roadmap — partner with founders and product to define priorities, make architectural decisions, and ensure engineering investments align with company goals.

• Set engineering standards — establish best practices for code quality, system design, incident response, and on-call culture.

• Drive delivery — keep the team focused and unblocked, managing execution across sprints, projects, and longer-horizon initiatives.

• Architect for scale — lead the design of our HSA/FSA payment infrastructure, APIs, and checkout experiences to handle growing merchant and transaction volume.

• Engage cross-functionally — work closely with customers, sales, and operations to translate real-world needs into engineering priorities.

• Stay hands-on — roll up your sleeves when it counts; you're comfortable contributing directly to the codebase when needed.

Who You Are

• 8+ years of engineering experience, with at least 2–3 years in an engineering leadership role (EM, Staff/Principal, or Head of Eng).

• Proven team builder — you've hired, grown, and retained strong engineers, and you know what great engineering culture looks like.

• Strong technical foundation — you have depth in backend systems and APIs, and you're conversant across the full stack. Familiarity with TypeScript, Rust, Postgres, Redis, and AWS is a strong plus.

• Architectural thinker — you've designed and scaled distributed systems and know how to make the right tradeoffs between speed and rigor.

• Startup experience — you've worked at a seed-to-Series B company and understand what it means to build in a resource-constrained, fast-moving environment.

• Operator mindset — you bring structure and clarity without bureaucracy, and you know how to keep a small team moving fast.

Mindset

• Low ego — open to feedback, comfortable with ambiguity, and focused on outcomes over credit.

• Collaborative — you bring people together and build alignment across teams.

• High standards — you care deeply about quality and push the team to do their best work.

• Strategic and scrappy — you can zoom out to think about the long term and zoom in to ship what matters now.

Why Join Flex

• Define the engineering function at a company with a clear wedge in a $150B+ market.

• Work directly with founders on the highest-leverage technical and product decisions.

• Competitive salary with meaningful equity.

• Medical, dental, and vision plans.

• Unlimited PTO and sick days.

• Paid parental leave.

• Flexible, remote-first team with quarterly in-person meetups.

Flex is an equal opportunity employer and encourages applicants from all backgrounds and life experiences. We celebrate diversity and do not discriminate based on race, religion, color, national origin, sexual orientation, gender identity, gender expression, age, veteran status, disability status, or any other legally protected characteristic.