Flex

Market position

Flex positions itself around the pool of HSA/FSA funds that go unspent each year, citing $1.5B in dollars forfeited annually and roughly 30% average pre-tax savings for consumers who use these accounts. The available sources do not name competitors or provide market share data.

The platform combines an HSA/FSA checkout payment method with in-flow eligibility substantiation: a chat-based telehealth consultation with a licensed clinician that can produce a Letter of Medical Necessity covering purchases for 12 months, plus automatically generated itemized receipts. It also supports split payments and fallback to credit/debit cards with reimbursement documentation.

Technology

Flex offers an HSA/FSA payment integration with a public API, developer guides, and a Flex MCP server enabling AI assistants (e.g., Claude, Cursor) to connect to a Flex account. The consumer flow includes a chat-based telehealth consultation used to determine Letter of Medical Necessity eligibility, and automated generation of itemized receipts and LMN documents for administrator submission.

Go-to-market

Flex distributes through merchant partnerships, appearing as a payment option at partner brand checkouts, and through its own marketplace and brand directory that aggregates 1,000+ HSA/FSA-eligible brands. It also publishes a blog, marketing assets for partners, and developer documentation to support merchant integration.

Two sides: U.S. consumers who hold HSA or FSA balances and want to spend them on eligible health, wellness and home products; and direct-to-consumer health and wellness brands and merchants (including gyms and studios) that want to accept HSA/FSA payments at checkout.

Geography

United States; the product is built around U.S. HSA and FSA accounts and IRS guidelines for medical necessity substantiation. No specific office locations are stated in the sources.

Risks & controversies

Flex's model depends on IRS rules governing HSA/FSA eligibility and Letters of Medical Necessity; its own materials note that LMN documentation should be retained for at least three years in case of an IRS audit and that FSA administrators may request the letter to confirm eligibility. The sources provide no information on regulatory actions or disputes. Note also that several unrelated companies share the "Flex" name (a public advanced-manufacturing firm, a fintech for middle-market business owners, and a seed-stage venture firm), creating identification risk in third-party data.