Flex

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Arek and Ethan 🦄

Flex allows consumers to make purchases with their HSA and FSA accounts online. Businesses can integrate Flex as a payment method at checkout via its Shopify integration or directly through its API. The company offers businesses features, including integrating Letter of Medical Necessity generation, splitting carts between eligible and ineligible items, dynamic discounting, and more. It also offers Flex Market, a marketplace for FSA/HSA-eligible products, directly to customers.

Check it out: withflex.com

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Flex works directly with enterprises for sales. Brands looking to use Flex for reimbursements are charged a one-time $99 setup fee, and clients are charged $15 per Letter of Medical Necessity.

• Raised $15 million Series A led by First Round and Core Innovation Capital with participation from Y Combinator, Rethink Impact, Liquid 2 Ventures, and Cameron Ventures

• Participated in Y Combinator S23 batch

• Partnered with brands such as Alo Yoga, iFIT, Therabody, NordicTrack, and more

• Customer Success Manager

• Enterprise Account Executive

• Mid Market Account Executive

• Support Engineer

• Software Engineer

Before founding Flex, CEO Sam O’Keefe and CTO Miguel Toledo met while working at Unit21, a fintech startup. O’Keefe wanted to combine fintech with fitness and health, leading the duo to research the market and interview merchants. This process led them to the inception of Flex.

O’Keefe brings over a decade of experience as an operator in tech. Her work encompasses being chief of staff and heading startup programs at Google Cloud, directing special projects at TechCrunch, and founding a B2B startup. Meanwhile, Toledo’s background consists of years of software engineering for companies including Lyft, Google, Equifax, and more.

As we near the end of 2025, an expected several billion dollars in FSA funds will be forfeited. While FSAs and HSAs are meant to pass pre-tax savings to consumers, these benefits are only as useful as the amount that is spent. Using spending account funds is often a headache, given that the guidelines for what items are considered eligible are not always straightforward. Other times, purchases require a Letter of Medical Necessity. All these hurdles taken together, it’s no wonder that so much money is more easily forfeited than spent.

This figure will only increase. According to Flex, the number of FSA/HSA accounts and contributions is increasing, and consumer wellness is now a $500 billion industry growing 5% per year. That means more money will be lost each year in unspent employee benefits. Flex is addressing this by providing products for both businesses and consumers meant to simplify the process of accepting and paying with FSA/HSA funds, respectively.

Flex boasts some impressive stats of its own. It claims that by using its product, checkout page conversions have increased by up to 30% with 50% more spent per cart. Its surveys show that 67% of customers only made their purchase because the merchant offered the ability to pay with their spending account. And its existing set of well-established partners only corroborates this story and emphasizes its strong product-market fit.

With a product that possesses strong revenue increases for businesses and a consumer-friendly mission, Flex is a win-win solution for health and wellness. After this holiday season, rather than seeing metrics of increased consumer spend, we’re curious to see just how much money Flex has helped consumers save.

• Flex: Stripe for HSA/FSA payments [Y Combinator]

• Flex Launches Flex Market: A New Way for Consumers to Maximize HSA/FSA Spending [Yahoo Finance]

• Flex Raises $15M to Unlock $150B in Unused HSA/FSA Funds [Flex]

• Workers Lose Over $4 Billion in Unspent FSA Money a Year [Money Magazine]

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