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. We're backed by First Round, Core VC, Rethink Capital power checkout for Equinox, Dermstore, Therabody, and Ultrahuman to name a few. 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.
We’re looking for a Frontend Engineer to own developing our applications that merchants and consumers rely on everyday. You’ll work closely with backend engineers, design, and business stakeholders to ship seamless experiences that make HSA/FSA simple, accessible, and easy to use.
This is a role for someone who thrives in ambiguity, takes initiative, and is excited about building at an early-stage company.
Lead frontend development using React across our multiple applications
Ship high-quality experiences with a bias towards execution
Partner with business stakeholders to ensure we’re addressing the needs of our merchants and consumers
Own and improve our frontend architecture while identifying and closing experience gaps across our applications
Collaborate on cross-functional projects that connect the full Flex experience, from consumer checkout to merchant analytics
Contribute to a culture of learning, problem-solving, and operational excellence
You have 5+ years of experience in software development, with an emphasis on modern frontend technologies and building delightful user interfaces
You have a strong understanding of modern web development best practices
You’re resourceful, curious, and comfortable learning new tools quickly
You thrive in fast-paced, dynamic environments and enjoy wearing multiple hats
You’re collaborative and enjoy working across teams to solve problems
You have an execution mindset and always keep the end user in mind
You're proficient at leveraging AI tools to ship faster
Experience with building frontend applications with React
Background in creating financial systems or tools leveraged by either merchants or consumers
A mission-driven team making healthcare spending effortless
Early-stage impact - your work will directly shape our growth and success
Collaborative, high-trust, and transparent culture
Competitive compensation and equity package
Flexible, remote-friendly work environment
Skills Required
- 5+ years of experience in software development
- Strong understanding of modern web development best practices
- Experience with building frontend applications with React
What We Do
Flex helps leading health and wellness brands increase AOV by up to 50% and boost checkout conversion by 30% with the only HSA/FSA payments infrastructure purpose-built for eCommerce.
