Flex
Flex is a B2B2C payment infrastructure platform that enables health and wellness brands to accept HSA and FSA payments at checkout, handling IRS eligibility verification and telehealth-based Letters of Medical Necessity, while operating a 1,000+ brand marketplace for pre-tax healthcare spending.
- Company typePrivate
- Founded2024
- HeadquartersSan Francisco, United States
- Headcount11–50
- GTM typeB2B
- OfferingSoftware
What Flex does
Flex is a B2B2C payment infrastructure platform that enables health and wellness brands to accept Health Savings Account (HSA) and Flexible Spending Account (FSA) payments. The company's core technology performs real-time IRS eligibility verification at checkout, processes HSA/FSA card transactions, and operates an optional telehealth-based Letter of Medical Necessity (LMN) service that expands the universe of eligible products — including supplements and other items not automatically recognized as qualifying medical expenses. The platform is embedded directly into partner brand checkout experiences and also surfaces through Flex Market, a consumer-facing marketplace aggregating 1,000+ eligible brands across fitness, skincare, sleep, recovery, women's health, and smart health.
Flex operates on a transaction-fee revenue model, charging partner brands for payment processing and compliance services. The company sells to enterprise brands (Equinox, Bluemercury/Macy's, Shiseido Americas, iFIT, Johnson Fitness & Wellness, Soundcore/Anker, Hyperice) and increasingly to long-tail SMB merchants via platform integrations such as SHOPLINE. Distribution is anchored by marquee partnerships that lend credibility to both consumer adoption and additional brand acquisitions. The company has processed over 2 million orders and is positioned against an estimated $150 billion in annual U.S. HSA/FSA contributions, of which roughly $1.5 billion is forfeited by consumers each year.
The company is venture-backed, headquartered in San Francisco, and led by CEO Sam O'Keefe. It has raised $18.2 million to date across a $3.2 million seed round in September 2024 and a $15 million Series A in September 2025 from investors including Y Combinator, SV Angel, Precursor, Liquid 2 Ventures, Core Innovation Capital, First Round Capital, Cameron Ventures, and Rethink Impact. Flex's GTM blends product-led infrastructure (embedded checkout, eligibility verification) with channel-partner expansion through marquee brands and e-commerce platforms, and it has been recognized on the Inc. 5000 list of fastest-growing private companies and Fast Company's Next Big Things in Tech.
Flex firmographics
Firmographics- Name
- Flex
- Legal name
- Flex Technology Co
- Website
- https://withflex.com
- Company type
- Private
- Founded year
- 2024
- Operating status
- Operating
- Headcount range
- 11–50 employees
- Short description
- Flex is a B2B2C payment infrastructure platform that enables health and wellness brands to accept HSA and FSA payments at checkout, handling IRS eligibility verification and telehealth-based Letters of Medical Necessity, while operating a 1,000+ brand marketplace for pre-tax healthcare spending.
- Ownership category
- akta.pro rank
Flex industry classification
Industry- Product category
- HSA/FSA Payment Infrastructure
- NAICS
- Health and Welfare Funds (525120), Health and Welfare Funds (52512), Insurance and Employee Benefit Funds (5251), Other Insurance Funds (52519), Other Insurance Funds (525190)
- SIC
- Accident & Health Insurance (6321), Insurance Agents, Brokers & Service (6411), Hospital & Medical Service Plans (6324)
- akta.pro primary industry
- Flexible Benefits Administration (FSA/HSA/HRA) (HLAEALAK)
Keywords
Where Flex is headquartered
LocationHeadquarters
- HQ city
- San Francisco
- HQ country
- United States
- HQ region
- North America
Offices1 record
Markets served
Flex business model
Business model- GTM type
- B2B
- Offering type
- Software
- Cost components
- Technology or R&D, Personnel, Marketing or Sales, Operations, Supply Chain
Revenue model
- HSA/FSA Payment Processing: Flex charges health and wellness brands for processing HSA and FSA payments through its platform. The company handles transaction processing, eligibility verification, compliance management, and optional LMN telehealth consultations.
- Marketplace Services: Flex Market aggregates partner brands into a consumer marketplace where users can shop across 1000+ HSA/FSA eligible brands, creating value for both brands (customer acquisition) and consumers (discoverability).
Pricing tiers
| Model | Billing | Price |
|---|---|---|
| Transaction based/ take rate | Pay-as-you-go | Standard HSA/FSA Payment Processing |
Go-to-market motion2 records
Distribution channels3 records
Marketing channels3 records
Flex product offering
Product offeringCore offering
Flex provides HSA/FSA payment infrastructure for health and wellness brands, integrating IRS eligibility verification, real-time checkout processing, and optional telehealth-based Letters of Medical Necessity into partner brand platforms. The company operates a consumer-facing marketplace (Flex Market) aggregating 1,000+ eligible brands across fitness, skincare, women's health, sleep, recovery, and smart health categories, enabling consumers to spend pre-tax healthcare dollars.
Product overview
Flex is an HSA/FSA growth platform that enables health and wellness brands to accept pre-tax healthcare payments. The core offering consists of the Flex HSA/FSA Marketplace (a consumer shopping destination), Flex payment infrastructure (for brand integrations), and Flex Market (a dedicated marketplace feature). The platform also offers an optional Letter of Medical Necessity (LMN) telehealth service that allows consumers to obtain medical verification for products requiring additional eligibility confirmation. Flex connects consumers with over 1000 partner brands across categories including fitness, skincare, sleep, smart health, women's health, nutrition, recovery, ergonomics, and eyewear.
Differentiator
Problem solved
Functional benefit
Brands
- Flex Market: A marketplace allowing consumers to maximize HSA/FSA spending across multiple health and wellness brands.
Quantifiable outcome
- Consumers forfeit approximately $450 in unspent HSA/FSA funds annually on average
- +2 more outcomes
Companies that use Flex
Customer profileNamed customers8 records
Segments5 records
Ideal customer profiles3 records
Flex technology and API
TechnologyTechnology focussed Yes
API detail
- Has API
- No
- API docs
- API detail
Core technology
AI maturity
App detail
Feature4 records
Flex partnerships and signals
Strategic signalPartnerships
14 partnerships are on record, tiered core, minor and major.
- JOONcoreJOON, a modern employee benefits platform, partnered with Flex to integrate Flex's HSA/FSA marketplace into JOON's system, combining employer-funded LSAs with employee-owned HSA/FSA dollars into a unified platform spanning fitness, wearables, women's health, sleep, and recovery.
- Bluemercury (Macy's Inc.)coreBluemercury partnered with Flex to enable customers to use pre-tax HSA/FSA funds for eligible products on Bluemercury.com. Over 2,300 products including SkinCeuticals and La Mer became HSA/FSA eligible. Bluemercury is the only luxury beauty retailer offering this capability online.
- Rent Now Pay Later ServicesminorMultiple sources mention Flex alongside Affirm and Livble for rent now pay later services, but this appears to be a separate Flex entity based on different business models and metrics.
- Equinox (Secondary Announcement)coreFollowing the initial partnership announcement, Equinox expanded HSA/FSA eligibility coverage as part of a broader industry shift toward integrating fitness with healthcare-aligned benefits.
- EquinoxcoreFlex partnered with Equinox to enable members to use HSA/FSA funds for select memberships, personal training, recovery experiences, and women's health programs. This was the first time Equinox enabled HSA/FSA eligibility, tapping into $150 billion in available HSA/FSA funds nationwide.
- CluecoreClue partnered with Flex to enable its 100+ million users to use HSA/FSA funds for Clue Plus subscriptions, offering estimated savings of 30-40% on reproductive health tracking subscriptions.
- Soundcore (Anker Innovations)majorSoundcore partnered with Flex to make its Sleep A30 smart ANC sleep earbuds eligible for HSA/FSA spending, powered by Flex's checkout and eligibility verification technology.
- Shiseido AmericascoreShiseido Americas partnered with Flex to enable HSA/FSA payments for purchasing skincare products online from brands including Dr. Dennis Gross Skincare, Clé de Peau Beauté, and Shiseido.
- SHOPLINEcoreSHOPLINE integrated Flex into its platform, enabling merchants to accept HSA/FSA cards directly at checkout and access the $150 billion U.S. health and wellness market, aiming to increase conversion rates and sales.
- Johnson Fitness & WellnessmajorJohnson Fitness & Wellness, a major fitness retailer, partnered with Flex to enable consumers to use HSA/FSA funds for fitness equipment purchases both online and in-store, leveraging over $150 billion contributed annually to HSA/FSA accounts.
- DermstoremajorDermstore partnered with Flex to expand access to dermatologist-recommended skincare products with HSA/FSA payment options.
- Alo MovesmajorAlo Moves partnered with Flex to allow members to use HSA/FSA funds toward subscriptions, providing access to 3,000+ yoga, fitness, and mindfulness classes with average savings of 30-40%.
- Flex Market LaunchcoreFlex launched Flex Market, a new marketplace allowing consumers to maximize HSA/FSA spending across multiple partner brands, aggregating 1000+ HSA/FSA eligible products.
- iFIT (NordicTrack, ProForm)majoriFIT partnered with Flex to bring HSA/FSA payment options to NordicTrack and ProForm customers, enabling pre-tax purchases of personalized fitness products.
Scale indicators7 records
Recent moves8 records
Expansion highlights6 records
Flex competitors and assessment
Company assessmentDirect peers
- Truemed: Truemed provides HSA/FSA payment infrastructure and Letter of Medical Necessity services for D2C health and wellness brands, operating a near-identical B2B2C model to Flex. It is the closest direct competitor in enabling LMN-driven HSA/FSA eligibility at brand checkout.
- Paytient: Paytient offers an HSA/FSA-linked payment and benefits card integrated with employers and health plans, enabling pre-tax healthcare spend. It overlaps with Flex on HSA/FSA payment infrastructure and target use cases, though distributed primarily through employer channels.
- HSA Store: HSA Store is an established online marketplace for HSA/FSA-eligible products. It competes with Flex Market on the consumer-facing discovery layer, though without Flex's embedded checkout infrastructure for partner brands.
Broad incumbents
- WEX (HealthEquity ecosystem): WEX operates in healthcare payment solutions and acquired benefits-adjacent assets, giving it scale and incumbent relationships across HSA/FSA-adjacent spend. It is comparable as a broader, well-capitalized incumbent that could bundle HSA/FSA checkout features.
- HealthEquity: HealthEquity is the largest independent HSA custodian in the US, holding member HSA funds and administering benefits. It is comparable as the dominant incumbent in HSA infrastructure, with resources to build or acquire D2C checkout integrations like Flex.
- Optum Financial (UnitedHealth Group): Optum Financial administers HSAs and other healthcare spending accounts for millions of Americans through UnitedHealthcare. It is comparable as a large incumbent with both payer relationships and HSA infrastructure that could integrate D2C HSA/FSA payment functionality.
- Fidelity HSA: Fidelity is one of the largest HSA custodians, holding a meaningful share of HSA account assets. It is comparable as a major incumbent with the scale and brand trust to extend into HSA/FSA-eligible commerce if strategically prioritized.
- Stripe (Health / Wellness vertical): Stripe is the dominant online payments processor for D2C brands including Flex's partners. It is comparable as an incumbent that could natively add HSA/FSA eligibility and LMN workflows, potentially disintermediating Flex's value layer at checkout.
Emerging players
- Mercer Marketplace: Mercer Marketplace provides employer-sponsored benefits platforms including HSA, HRA, and Lifestyle Spending Account administration. It overlaps with Flex's employer benefits ambitions (e.g., JOON partnership) as a more established channel-distribution player.
- Further (formerly Benefit Strategies): Further is a benefits administration platform offering HSA, FSA, HRA, and COBRA administration for employers. It is comparable as an emerging player building integrated pre-tax benefit spend experiences that increasingly touch D2C wellness commerce.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat5 records
Key risks6 records
Key highlights7 records
Customer concentration
Flex social profiles
Digital presenceFlex financial estimates
Financial estimateRevenue estimate
Valuation estimate
Flex leadership team
Management profileNumber of profiles
Profiles2 records
Flex funding detail
Funding detailFunding overview
Funding rounds3 records
Investors9 records
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
Flex M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about Flex
What does Flex do?
Flex provides HSA/FSA payment infrastructure for health and wellness brands, integrating IRS eligibility verification, real-time checkout processing, and optional telehealth-based Letters of Medical Necessity into partner brand platforms. The company operates a consumer-facing marketplace (Flex Market) aggregating 1,000+ eligible brands across fitness, skincare, women's health, sleep, recovery, and smart health categories, enabling consumers to spend pre-tax healthcare dollars.
Is Flex a public or private company?
Flex is a private company. It is classified as venture growth investor backed and is currently operating.
When was Flex founded?
Flex was founded in 2024. It employs 11 to 50 people.
Where is Flex based?
Flex is headquartered in San Francisco, United States, in the North America region.
How does Flex make money?
Two revenue lines are on record. HSA/FSA Payment Processing is the primary driver. The others are marketplace Services.
Who are Flex's main competitors?
Direct peers on record are Truemed, Paytient and HSA Store. Broad incumbents are WEX (HealthEquity ecosystem), HealthEquity, Optum Financial (UnitedHealth Group), Fidelity HSA and Stripe (Health / Wellness vertical). Emerging players are Mercer Marketplace and Further (formerly Benefit Strategies).
Does Flex have an API?
No public API is recorded for Flex.
What industry is Flex in?
Flex's product category is HSA/FSA Payment Infrastructure. Its primary akta.pro industry code is HLAEALAK, Flexible Benefits Administration (FSA/HSA/HRA). Its NAICS code is 525120 and its SIC code is 6321.