Stephen M. Walker II

Stephen is the founder of Fuel and writes most of the Fuel Journal. He builds nutrition coaching for the same audience he has shipped products to for a decade: people who take training seriously and want software that respects it.

From 2017 to 2020 he led product, design, research, content, and subscription monetization as Head of Product & Design at Freeletics, where his teams helped the digital fitness app surpass 50 million users worldwide across 100+ countries, with 70% week-one training activation. That stint — owning every surface that touches habit formation in a fitness app — is the operator lens behind every article here.

After Freeletics he grew Productboard 5x to $50M+ ARR as Senior Director of Product Management (2020–2022), reshaping the product from SMB/PLG-darling to enterprise roadmap software adopted by 6,000+ companies. Since 2022 he has been co-founder and CEO of Klu.ai, an LLM infrastructure platform used by thousands of AI teams — which is why Fuel's AI food logging and coaching feel less hand-wavy than most.

Earlier he ran global UX programs at Amazon (2016–2017) for cross-border eCommerce, led mobile investing design at Capital One (2014–2016), and spent a decade (2003–2014) running Smoov, a boutique design studio shipping work across consoles, desktop, mobile, and web. He speaks regularly at EU CPO Conference, SXSW, La Product Conf, and Product Led Alliance. Verifiable on SMW.ai, LinkedIn, and Speaker Deck.