How American Express 4x Its Experimentation Velocity in 1 Year

Every product leader wrestles with the same tradeoff: move fast and risk breaking things, or move slow and risk irrelevance. But what if the real accelerator wasn’t cutting corners—it was systematizing experimentation? In this episode, Hannah Clark sits down with Jean Castanon, VP of Digital Product at American Express, to explore how his team quadrupled their testing velocity in a year, redefined what “success” in experiments really means, and built a referral program that became Amex’s second-largest global acquisition channel.

Jean brings over a decade of experience at Amex across strategy, marketing, and digital, and he shares how his team balances speed, scale, and sustainability in product strategy. From building experimentation muscle to future-proofing digital storefronts, this conversation is packed with lessons for product leaders at every stage.

What You’ll Learn

  • Why speed in product strategy doesn’t have to mean recklessness
  • How to build an “always on” experimentation ecosystem
  • Ways to align cross-functional teams around a single North Star metric
  • The mindset shift that reframes failed experiments as valuable learning
  • How Amex scaled its referral program into a global growth engine
  • The role AI and personalization play in shaping digital storefronts

Key Takeaways

  • System beats sprints: Moving faster comes from structured experimentation, not just pushing harder.
  • One language, one metric: A shared goal (like conversion lift) creates alignment across product, design, engineering, and marketing.
  • Dedicated focus matters: A team tasked only with experimentation avoids being swallowed by shifting priorities.
  • Failure ≠ wasted effort: Reframing experiments as learning opportunities builds resilience and accelerates growth.
  • Build for scale early: Treat referral programs and similar initiatives as products in their own right, with infrastructure, controls, and personalization baked in.
  • Future-proof through agility: Upskilling teams and modernizing digital storefronts are non-negotiables for competing with fintechs and evolving consumer expectations.

Chapters

  • [00:00] The tradeoff every product leader faces
  • [01:13] Jean Castanon’s path to VP of Digital Product at Amex
  • [02:23] What forward-thinking strategy looks like in an established company
  • [03:54] Scaling experimentation: from 30 tests to 120+ in one year
  • [05:32] Aligning cross-functional teams on a single metric
  • [08:00] Building team capacity without burning out
  • [09:35] Redefining success: why failed experiments are valuable
  • [11:39] Case study: Amex’s referral program growth
  • [14:09] Early AI pilots in experimentation and productivity
  • [15:32] Personalizing the digital storefront for new prospects
  • [16:41] Trends shaping financial services customer acquisition
  • [18:55] Where to connect with Jean

Meet Our Guest

photo of Jean Castanon

Jean Fernand Castanon is a seasoned digital product leader at American Express, currently serving as Vice President of Enterprise Referrals & Shop in London. With over 13 years of expertise in payments and digital innovation, his career spans product management, marketing, analytics, and business development—rising from analyst positions to executive leadership to steer acquisition strategies and marketplace differentiation. Holding an MPhil from the University of Cambridge and a BSc from the University of Manchester, Jean blends academic rigor with international experience across London and New York to deliver impactful customer experiences.

Resources from this episode:

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