Zaid Rahman is the founder and CEO of Flex, a breakout fintech startup that’s reinventing credit and payments for the middle market. Backed by the Thiel Fellowship and known for his “Delta 4” product philosophy, Zaid is building a multi-product platform that’s helping profitable, owner-operated businesses unlock capital and scale faster.
In this conversation, Zaid breaks down how Flex is using AI to radically reduce underwriting time, why he’s obsessed with hiring 10x talent, and how “taste” and first principles thinking guide everything from product design to risk management. If you’re building in fintech, hiring in tech, or just obsessed with the craft of company-building, this episode is full of tactical insight.
The Delta 4 framework: how to build products people rave aboutFlex’s competitive edge vs. Brex, Ramp, and legacy banksHow Flex slashed credit underwriting time from 25 days to 48 hours using LLMsWhy Zaid believes fintech is “still day one” in 2025How to spot first-principles thinkers in interviews (and why “best practices” is a red flag)Why Flex targets the “jumbo shrimp” of the middle marketHow Zaid built a 250+ member Thiel Fellow community from scratchThe real cause of burnout—and how to build a sustainable high-performance cultureZaid Rahman is the founder and CEO of Flex, a fintech platform serving mid-market businesses with credit, payments, and financial tools. A recipient of the prestigious Thiel Fellowship, Zaid previously founded multiple startups and is known for his rigorous hiring philosophy, taste-driven leadership, and commitment to building “Delta 4” experiences.
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Juniper Square is dedicated to transforming the private markets investing experience. The company provides a full range of modern, connected fund technologies and services for over 2,100 private markets GPs across fundraising, reporting, fund administration, treasury, compliance, and business intelligence. Today, over $1 trillion of assets and 600,000+ LP accounts are managed through Juniper Square software and fund administration services. Learn more at www.junipersquare.com/vc.
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David Weisburd: @dweisburd
David Weisburd: https://www.linkedin.com/in/dweisburd/
Zaid Rahman: https://www.linkedin.com/in/zaidrahman/
Flex: https://www.linkedin.com/company/flex-super-app/
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(0:00) Episode preview
(2:14) David Weisburd: Benefits of the Teal fellowship and creating a WhatsApp group for fellows
(4:44) David Weisburd: Using AI for credit underwriting at Flex
(8:14) David Weisburd: AI's impact on efficiency and differentiating Flex from competitors
(11:36) David Weisburd: Recruitment strategy and identifying team members with good taste
(20:59) David Weisburd: Evaluating candidate contributions and defining unique positions
(24:44) Understanding customer priorities and the importance of first principles thinking
(27:09) Learning through interviews and the challenge of finding the right hire
(31:06) Balancing expertise and culture fit in hiring and the role of non-10x employees
(38:23) Addressing burnout in a high-intensity work environment
(40:54) The future of FinTech and Flex's vision
(46:27) Closing remarks