About Flex
Flex is a company based in San Francisco (United States) founded in 2023 by Sam OKeefe. It operates as a API-as-a-Product and FinTech. Flex has raised $18.7 million across 3 funding rounds from investors including Heirloom Ventures, Y Combinator and SV Angel. Flex offers products and services including HSA/FSA Payment Infrastructure, Shopify Payment App, Web API Checkout, and Letter of Medical Necessity. Flex operates in a competitive market with competitors including Greenphire, Cedar, Zelis Healthcare, PayZen and Alegeus, among others.
- Headquarter San Francisco, United States
- Founders Sam OKeefe
- SectorsFinancial Services
- Website category Business and Consumer Services · Business Services
- Email••••••••
- Website withflex.com
- Social LinkedIn X
- Total Equity Funding$18.7M (USD)
in 3 rounds
- Latest Funding Round$15M (USD), Series A
Sep 2025
- InvestorsHeirloom Ventures
& 8 more
Products & Services of Flex
Flex offers a comprehensive portfolio of products and services, including HSA/FSA Payment Infrastructure, Shopify Payment App, Web API Checkout, and Letter of Medical Necessity.
HSA/FSA payments are enabled for seamless checkout experiences.
HSA/FSA payments are integrated into Shopify checkout systems.
API for HSA/FSA payments is provided for websites.
Compliance with HSA/FSA rules is supported through documentation.
Funding Insights of Flex
Flex has successfully raised a total of $18.7M across 3 strategic funding rounds. The most recent funding activity was a Series A round of $15 million completed in September 2025. This substantial capital infusion reflects strong investor confidence in the company's business model, growth potential, and market opportunities. The funding enables strategic expansion, product development, market penetration, and operational scaling to drive long-term value creation and competitive advantage.
- Total Funding $18.7M
- Total Rounds 3
- Last Round Series A — $15M
- First Round $500,000
(Jun 2023)
- Investors Count 9
All 3 funding rounds of Flex with amounts and investors; the two latest post-money valuations are shown, the rest are part of the premium plan.
| Date | Amount | Transaction Name | Valuation | Lead Investors | Investors |
|---|---|---|---|---|---|
| Sep 2025 | $15M | Series A | – | First Round Capital, Core Innovation Capital | |
| Sep 2024 | $3.2M | Seed | – | Y Combinator, SV Angel | |
| Jun 2023 | $500,000 | Seed | – | – | – |
9 investors in total: 9 institutional.
Investors in Flex
Flex has secured backing from 9 investors, including venture fund and institutional investors. Prominent investors backing the company include Heirloom Ventures, Y Combinator and SV Angel.
| Investor | Description | Founded Year | Domain | Location |
|---|---|---|---|---|
Early-stage startups are accelerated via funding and educational programs. | – | ycombinator.com | Mountain View, United States | |
Early-stage investments are provided to transformative technology companies. | – | svangel.com | San Francisco, United States | |
Venture capital investments in pre-seed and seed stages, focusing on founders. | – | precursorvc.com | - | |
Venture capital fund focused on seed-stage investment in multiple sectors | – | liquid2.vc | San Francisco, United States | |
US focused seed and early-stage VC firm | – | firstround.com | San Francisco, United States | |
Venture capital investments in fintech and technology for wealth and health. | – | corevc.com | - | |
Life sciences and tech focused impact VC firm funding companies in the US, the UK and Canada | – | rethinkimpact.com | Washington, Dc, United States | |
Heirloom Ventures is structured as a holding company since 2016. | 2016 | heirloomholdings.com | - | |
- | – | cameron.vc | - |
Investor details for Flex
The complete investor list, round-by-round participation and investor portfolios require an active premium plan.
- Complete investor list
- Round participation
- Investor portfolios
- Co-investor network
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People of Flex
8 people are tracked at Flex (4 in leadership, 4 in team).
| Name | Role | Group |
|---|---|---|
Sam OKeefe | Co-Founder & CEO | Leadership |
Miguel Toledo | Co-founder | Leadership |
Ben Noblet | Head Of Partnerships | Leadership |
Nick Holland | Head Of Growth | Leadership |
Varsha P. | Founding Software Engineer | Team |
Devon Navon | Data Engineer | Team |
David Barratt | Founding Engineer | Team |
Philip Chen | Growth Advisor | Team |
Complete people profiles for Flex
Full employee and board profiles, team structure, tenure and professional contact details require an active premium plan.
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Timeline of Flex
3 dated milestones of Flex across 2 years, from founding to its latest funding, stage changes and deals.
- Founded Flex is founded.
- Funding First funding round of $500K.
- Funding Latest funding round, Series A, of $15.0M.
Competitors of Flex
Flex operates in a dynamic and competitive business environment, facing competition from various established players and emerging companies in the market. The competitive landscape includes prominent companies such as Greenphire, Cedar, Zelis Healthcare, PayZen and Alegeus, among others.
| Company Name | Domain | Founded | HQ Location | Total funding | Employees | Description |
|---|---|---|---|---|---|---|
| greenphire.com | 2007 | King Of Prussia, United States | $5.81M | 259 | Clinical payment technology for patient transactions in research is provided. | |
| cedar.com | 2016 | New York, United States | $351M | – | Cloud-based payment solutions are provided for healthcare billing and analytics. | |
| zelis.com | 1995 | Boston, United States | – | 2,336 | Digital solutions to modernize the healthcare financial experience for payers, providers, and members | |
| payzen.com | 2011 | San Francisco, United States | $72M | – | AI medical billing software for healthcare professionals and organizations | |
| alegeus.com | 1995 | Waltham, United States | – | 696 | Healthcare benefits are administered via tax-advantaged account platforms. | |
| revspringinc.com | 1981 | St. Paul, Canada | – | 695 | Revenue cycle management platform for healthcare centers is offered. | |
| withcherry.com | 2017 | San Francisco, United States | – | – | Sales payment solutions are provided for businesses and customers. | |
| visitpay.com | 2010 | Boise, United States | $53.62M | 101 | Cloud-based patient revenue management is delivered to healthcare providers. | |
| instamed.com | 2004 | Philadelphia, United States | $123.24M | 275 | Healthcare bill payments are facilitated for providers and patients. | |
| healthipass.com | 2013 | Lombard, United States | $11.28M | – | Automated healthcare billing and patient account management are facilitated. |
Detailed competitors of Flex
The full competitor set, operating metrics and side-by-side benchmarks require an active premium plan.
- Full competitor set
- Operating metrics
- Benchmarks
- Competitive positioning
Verified entity values are shown only after access is granted.
Web traffic of Flex
The website of Flex (withflex.com) receives about 333.4K visits a month and ranks #83,097 among all websites worldwide, #2,117 in Business Services.
- Monthly visits333.4K
▼ 58.8% vs previous month
- Unique visitors392.4K
per month
- Global rank#83,097
among all websites
- Category rank#2,117
Business and Consumer Services · Business Services
- Bounce rate66%
- Pages per visit1.8
- Average visit2 min 14 sec
- DevicesDesktop 5% · Mobile 95%
Websites whose visitors overlap most with Flex. Affinity shows how closely the audiences match.
| Website | Domain | Audience affinity | Monthly visits | Global rank | Profile |
|---|---|---|---|---|---|
| goauntflow.com | 100% | 43.5K | #768,502 | View details | |
| shopify.com | 73% | 224.7M | #101 | View details | |
| truemed.com | 64% | 997.7K | #51,573 | View details | |
| zillow.com | 56% | 321.9M | #68 | View details | |
| linkedin.com | 25% | 1.9B | #18 | View details |
Latest news on Flex
Complete news archive for Flex
Full article history, source details, and older brand coverage require an active premium plan.
- Full article archive
- Source and publication date
- Older coverage
- Brand-specific news history
Verified entity values are shown only after access is granted.
Similar companies to Flex
10 companies that operate in the same segment as Flex (Payments & Remittance Platforms), ranked by their profile score on The Company Check.
| Company | Description | Founded | Location | Total funding | Revenue | Employees |
|---|---|---|---|---|---|---|
Digital payments, financial services, and e-commerce platforms are provided. | 2000 | Noida, Uttar Pradesh, India | USD 4.14 B | – | – | |
Payment, financial, investment, and lending services are provided digitally. | 2012 | Bengaluru, Karnataka, India | USD 1.71 B | – | – | |
Payment processing and card issuance solutions are provided for businesses. | 2009 | San Francisco, California, United States | USD 9.81 B | – | – | |
Cloud-based accounts payable and receivable software for businesses | 2006 | Palo Alto, California, United States | USD 325.6 M | USD 1.65 B | 2,360 | |
Payment and business banking solutions are provided for enterprises. | 2014 | Bengaluru, Karnataka, India | USD 742 M | USD 302.19 M | 2,641 | |
Spend management and accounts payable solutions are delivered to businesses. | 2019 | New York, New York, United States | USD 3.21 B | – | – | |
Payment acceptance and processing solutions provider for businesses | 2018 | Gurugram, Haryana, India | USD 604.02 M | USD 179.52 M | 709 | |
Business spends, payments, and rewards are streamlined by automated workflows. | 2011 | Hyderabad, Telangana, India | USD 13.75 M | USD 149.43 M | 431 | |
Online payment processing and credit solutions are provided for businesses. | 2002 | Amsterdam, Netherlands | USD 35.15 M | USD 5.47 B | 1,200 | |
SaaS-driven credit card and spend management solutions platform for businesses | 2017 | Draper, Utah, United States | USD 1.16 B | – | 1 |
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Frequently Asked Questions about Flex
Flex was founded in 2023.
Flex is headquartered in San Francisco, United States. It is registered at San Francisco, California, United States.
Sam OKeefe is the current CEO of Flex. They have also founded this company.
Flex is a funded company, having raised a total of $18.7M across 3 funding rounds to date. The company's 1st funding round was a Seed of $500K, raised on Jun 2023.
HSAFSA payment infrastructure is offered by Flex to enable seamless transactions for health and wellness brands. Solutions are designed for e-commerce integration, supporting Shopify, web APIs, and compliance tools like Letters of Medical Necessity. Industries such as fitness, skincare, and supplements are served, with a focus on increasing conversion rates and average order values. Enterprise-scale operations, including subscriptions and high-volume transactions, are supported through customizable and reliable technology.
Flex's top competitors include Greenphire, Cedar and PayZen.
Flex offers HSA/FSA Payment Infrastructure, Shopify Payment App, Web API Checkout, and Letter of Medical Necessity.
Flex has 9 investors. Key investors include Heirloom Ventures, Y Combinator, SV Angel, Precursor Ventures, and Liquid 2 Ventures.
The website of Flex receives about 333 thousand visits a month and ranks #83,097 among all websites worldwide.