Latest Interviews

How to Make Claude Code Your AI Engineering Team

Garry Tan, Gary

Gary Tan, President and CEO of Y Combinator, has launched GStack, an open-source framework that restructures AI coding assistants into specialized engineering teams to overcome current limitations in model scaffolding. The system utilizes skills like Adversarial Review and the Office Hours query to automatically identify design flaws, generate multiple UI variants, and process hundreds of daily pull requests without traditional to-do lists. With over 70,000 GitHub stars, GStack shifts developer focus from manual coding to strategic oversight, enabling the management of parallel AI sessions to accelerate software factory operations from ideation to production.

Colour visions: a German-election lookahead

Rosie Bloor, Jason Palmer, Tom Nuttall, Moeka Iida, Jeff Goddard, Charlotte Kilpatrick

Germany's upcoming federal election features a fragmented parliament where Chancellor candidate Friedrich Merz leads polling but faces complex coalition hurdles due to the AfD's exclusion and the precarious status of smaller parties like Die Linke and the BSW. Simultaneously, Japan is undergoing a cultural reckoning following the resignation of celebrity Nakai Masahiro for assault, sparking public outrage that exposes deep-rooted legal and societal barriers despite recent reforms raising the age of consent. In London, the traditional pie and mash shops that defined Cockney culture since the Victorian era are vanishing due to rising rents and demographic shifts, forcing surviving establishments to diversify menus with vegan options to adapt to changing customer bases.

Scam Inc 2: Opportunity of a lifetime

Zannie Minton-Beddoes, Sulin Wong

Recruited through deceptive job postings, victims from the Philippines, Uganda, South Africa, and South Asia are smuggled into remote Myanmar compounds where they are held captive and forced to execute "Pig Butchering" cryptocurrency scams. These workers endure 16-hour shifts and brutal physical punishment while impersonating wealthy professionals to defraud White Americans aged 40 to 65 of tens of thousands of dollars. Controlled by Chinese-led hierarchies and increasingly industrialized by satellite-confirmed infrastructure, these self-contained operations utilize deepfake technology and strict racial targeting to sustain a vast, transnational fraud network.

Stripe Head of Design Katie Dill Reviews Startup Websites

Katie Dill, Aaron Epstein

This session establishes core web design principles prioritizing immediate value clarity and mobile responsiveness while critiquing six specific healthcare and B2B technology sites. Reviewers identified critical usability failures across these platforms, including excessive scrolling on Mito Health, visual clutter on Cygnaz, and confusing brand identity on Taiv, which collectively risk user abandonment. The discussion concludes with actionable recommendations to align visual hierarchy, consistent typography, and clear calls-to-action with user scanning behaviors to boost trust and conversion rates.

How To Convert Customers With Cold Emails | Startup School

Aaron Epstein

This event details a data-driven outreach framework where founders must personally execute high-volume email campaigns using warm introductions or targeted cold strategies to secure B2B customers. The speaker outlines a specific funnel architecture that requires sending dozens of daily messages while applying seven principles of effective copy, such as humanized tone, deep personalization, and clear calls to action, to maximize response rates. By analyzing case studies of both failed and successful campaigns, the presentation emphasizes that manual, founder-led execution is essential for building initial traction before any automation is introduced.

How To Keep Your Users | Startup School

David Lieb

YC Group Partner David Leib leverages his experience scaling Bump and Google Photos to argue that high cohort retention is the definitive quantitative signal of product-market fit. He details precise methodologies for defining user actions, selecting appropriate measurement intervals, and interpreting retention curve shapes to distinguish sustainable growth from a churn-heavy treadmill. By avoiding common analytical pitfalls and applying strategies like user acquisition targeting and onboarding optimization, founders can transform cohort data into a actionable roadmap for building scalable, long-term businesses.

Down to the wires: Africa’s digital lag

Rosie Bloor, Jason Palmer, Ore Ogunbiyi, Sophie Pedder, John Bleasdale

The event analyzes Africa's critical digital infrastructure deficit, highlighting how energy shortages and regulatory barriers threaten to exclude the continent from $16 trillion in potential AI-driven economic growth. It further examines the Paris Olympics' environmental contradictions, where a billion-euro cleanup of the Seine failed to prevent bacterial contamination during the triathlon despite the river's vital role in global logistics. Finally, the discussion retrospectively evaluates the enduring success of the *Blair Witch Project*, detailing its record-breaking $250 million return on a $35,000 budget through innovative viral marketing and psychological storytelling techniques.

Enterprise Sales | Startup School

Pete Koomen, Pete Kuhman

Optimizely co-founder Pete Kuhman outlines a rigorous enterprise sales framework for technical founders, emphasizing that selling before product-market fit requires experimentation with targeted prospecting and personalized outreach. The strategy prioritizes deep discovery during initial calls, uses product-specific narratives to demonstrate value during demos, and treats pricing as a signal of problem severity rather than a fixed metric. By actively managing implementation roadmaps to ensure customer adoption and navigating procurement hurdles with internal champions, founders can transform sales skills into a transferable superpower for fundraising and hiring.

OCaml Locals Save Allocations | OCaml Unboxed

goldfirere

Jane Street demonstrates how a specialized OCaml compiler reduces memory allocation by introducing the `local` keyword, which restricts value lifetimes to specific function and loop regions. This approach requires replacing standard library functions like `list.iter` with custom implementations that explicitly label arguments as `local` to prevent value escapes, achieving a 50% reduction in word allocations in benchmark tests. Further refinements with the `exclave` keyword and strict type inference drive allocation overhead to near-zero, thereby minimizing garbage collection latency for the experimental feature planned for future upstream integration.

Inferring Locality in OCaml | OCaml Unboxed

The OCaml compiler utilizes an internal allocation discipline that infers local versus global modes for variables and parameters to enable stack-based memory usage and reduce garbage collection overhead. This system prioritizes local inference for arguments while defaulting return values to global to ensure maximum compatibility, with integers serving as a special case that can safely cross mode boundaries under specific annotations. Although this framework enhances performance, current limitations such as standard library functions lacking locality awareness and the need for explicit type signatures to trigger safety checks continue to shape its practical application.

Consumer Startup Metrics | Startup School

Tom Blomfield

Founder guidelines for consumer startups define 15% month-over-month growth as the ideal benchmark while emphasizing that viral loops and network effects provide sustainable value compared to paid acquisition. Strategic analysis mandates rigorous tracking of customer acquisition costs against retained users to ensure positive unit economics, alongside defining retention "magic moments" and maintaining a Net Promoter Score above +50 to validate product-market fit. Companies achieving long-term scale typically prioritize an 80:20 split favoring organic channels to mitigate the risks of diminishing returns and platform dependency inherent in over-reliance on paid growth.

B2B Startup Metrics | Startup School

Tom Blomfield

This session guides early-stage founders on establishing a rigorous foundational metrics strategy that prioritizes revenue, burn rate, and Net Dollar Retention over vanity data to ensure financial viability. It details how to define consistent unit economics and gross margins, warning that negative unit economics in the current high-interest environment require immediate product or pricing fixes before any scaling efforts. The presentation concludes by balancing these quantitative requirements with the necessity of direct customer interaction, urging leaders to use data to inform decisions rather than replace human empathy and intuition.

Design Tips to Convert More Customers | Design Review

Aaron Epstein, Pete Koomen

Optimizely co-founder Pete Kuman analyzes how four distinct SaaS platforms manage their conversion funnels, contrasting Rivet's confused user experience caused by conflicting calls to action against Decoherence's successful strategy of minimizing friction through social proof and repeated "start free trial" prompts. While Decoherence excels at top-of-funnel acquisition, the discussion highlights critical gaps in onboarding guidance, whereas Solve Intelligence and InEvent illustrate how poor audience targeting, unclear value propositions, and buried features can severely hinder conversion despite strong social credentials. The episode concludes by emphasizing the necessity of mapping user journeys to eliminate redundant steps and guide visitors efficiently toward their "aha moment."

How Startup Fundraising Works | Startup School

Brad Flora

This analysis debunks seven common fundraising myths by contrasting misconceptions with evidence from companies like Fresh Paint, Retool, and Zapier. It argues that founders should prioritize building a minimal viable product to demonstrate utility, utilizing standardized tools like the SAFE agreement to secure seed capital quickly while retaining total control. The presentation concludes that current market conditions offer unprecedented access to capital, urging entrepreneurs to focus on product-market fit rather than networking or pitch perfection.

Startup Business Models and Pricing | Startup School

Aaron Epstein

This analysis identifies nine primary business models, with marketplaces and transactional ventures dominating Y Combinator's top companies due to their ability to generate network effects and capture significant value from financial flows. The discussion emphasizes that recurring revenue and high retention rates create defensible moats, while early-stage startups achieve scale by copying proven structures rather than mixing multiple models. Furthermore, founders are advised to charge immediately based on perceived value, using simple pricing strategies and gradual increases to validate demand and maximize long-term revenue.