Founding Solutions Architect

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.

We're backed by First Round, Core VC, Rethink Capital power checkout for Equinox, Dermstore, Therabody, and Ultrahuman to name a few. The category we're building didn't exist two years ago, and the enterprise opportunity in front of us is the next chapter.

About the Role

This is the highest-leverage Solutions Architecting job we'll ever hire for. As our Founding Solutions Architect, you own the technical motion for every strategic and enterprise deal at Flex. You won't be parachuted in for a single demo and pulled back out. You'll be embedded with sales from first call through contract, integration, and expansion, and you'll be the person who turns "this looks interesting" into a signed and live merchant.

You'll also be the loudest voice of the customer inside Flex. The patterns you spot in enterprise conversations, the integration shapes prospects keep asking for, the compliance gaps that block deals, and the capabilities competitors are claiming, flow directly into product and engineering's roadmap. We don't have a PMM filtering this for us yet. You are that signal.

You'll work directly with our VP of Sales and CTO, alongside our founders, sales team, and engineering org.

What You'll Own

• The technical narrative for every enterprise deal, from first discovery call through security review, integration design, and go-live

• Custom integration architectures for complex merchant-built checkouts. The bulk of this work is direct API integration with sophisticated, custom commerce stacks

• Live POCs, sandbox demos, and integration walkthroughs that move six- and seven-figure deals across the line

• The structured feedback loop into product and engineering, synthesizing what enterprise prospects need, where we're losing on capability, and where the next durable bet is

• Reusable enablement assets, including reference architectures, integration playbooks, security and compliance one-pagers, and ROI models that scale the GTM team

• Smooth handoff to customer success and engineering for post-sale implementation

Who You Are

• 7+ years in Solutions Architecture, Sales Engineering, or Solutions Engineering, with at least 3 years selling into enterprise

• You've owned the technical side of complex, multi-stakeholder deals. The kind that involve a CTO, a CISO, a head of e-commerce, and a procurement team all in the same Slack channel

• You can read API docs, sketch an integration on a whiteboard, and ship a working POC when a deal calls for it. You don't need an engineer in the room to be technically credible

• Background in payments, fintech, e-commerce, or healthtech is strongly preferred HSA/FSA, benefits, or regulated payments is a major plus

• You've built feedback channels into product orgs that engineers actually trust, not just forwarded customer emails

• You write well. Crisp follow-ups, clean architecture diagrams, briefs an exec can read in 90 seconds

• Comfortable in early-stage chaos. You've been at a seed or Series A/B company before and you know what "first one in the seat" actually feels like

How You Think

• You translate fluently between a CTO, a compliance officer, and a marketing lead, and you know which version of the answer each one needs

• You get energy from being in front of customers, not behind a deck

• You instrument what you do. You can tell us in six months which assets moved deals and which didn't

• You're a builder. The first version of every playbook here will have your fingerprints on it

Compensation & Logistics

• OTE: $160,000 to $260,000, structured as base plus variable tied to enterprise pipeline and closed-won attainment

• Meaningful founding-team equity

• Medical, dental, and vision plans

• Unlimited PTO and sick days

• Paid parental leave

• Remote-first, with quarterly in-person meetups. Expect ~25% travel for prospect on-sites, partner conversations, and industry events

Why This Role, Why Now

• You'd be the first dedicated SA at a category-creating company in a $150B market. The deals you close and the assets you build define how Flex sells to enterprise for years

• You'd work directly with founders on the deals and product decisions that shape the company

• The technical surface area is meaty: complex direct API integrations, payments rails, eligibility logic, and healthcare compliance

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.