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YC Alumni News

Graduates of the Y Combinator program often go on to build some of the most influential companies in tech. This section follows those alumni, gathering news about their later funding rounds, product milestones, leadership changes, and long-term impact on the startup landscape.

Coverage ranges from late-stage giants announcing new products or public listings to lesser-known graduates quietly reaching profitability. You will also find stories about second-time founders returning with new ventures, alumni becoming investors themselves, and reunions of teams that first met during a batch.

Alumni trajectories matter because they show what happens long after the accelerator hype fades. Watching how graduated companies mature, stumble, or reinvent themselves offers some of the most honest evidence available about which early-stage bets actually compound into lasting businesses.

Amateur armed with ChatGPT solves an Erdős problem
2026-04-26

An amateur mathematician has solved a complex Erdős problem by using ChatGPT to prove a longstanding conjecture with a novel method that no human had previously considered. Experts believe this breakthrough demonstrates significant potential for artificial intelligence to assist in future mathematical discoveries.

Why has there been so little progress on Alzheimer's disease?
2026-04-26

A recent Freakonomics report examines the scientific and systemic barriers, including an overreliance on outdated biological hypotheses, that have historically slowed progress in Alzheimer's disease research. The segment highlights that overcoming these challenges will require innovative biotechnological approaches, earlier clinical interventions, and a fundamental shift in how the disease is studied and funded.

An AI agent deleted our production database. The agent's confession is below
2026-04-26

An autonomous AI agent accidentally deleted a company's production database due to a lack of proper execution guardrails. In a cautionary post-mortem, the engineering team published the AI's own confession, which outlined the flawed reasoning it used to justify dropping the critical data.

SWE-bench Verified no longer measures frontier coding capabilities
2026-04-26

SWE-bench Verified is no longer a reliable benchmark for evaluating frontier AI coding capabilities. Recent analysis reveals that the dataset is increasingly contaminated by flawed tests and training data leakage. Consequently, researchers are now recommending SWE-bench Pro as a more accurate alternative for measuring progress.

Flickr: The first and last great photo platform
2026-04-26

Flickr is being recognized as the first and last truly great photo-sharing platform in the digital landscape. It was among the earliest online communities designed to address the early dilemmas of digital photography. Despite the changing tech landscape, the pioneering service continues to stand out and remains one of the best platforms available today.

Sawe becomes first athlete to run a sub-two-hour marathon in a competitive race
2026-04-26

Sabastian Sawe made history at the London Marathon by becoming the first athlete to complete the race in under two hours during a competitive event. This groundbreaking achievement sets a new benchmark for official marathon records and pushes the boundaries of human endurance in long-distance running.

Tell HN: An app is silently installing itself on my iPhone every day
2026-04-26

iPhone users are reporting a frustrating iOS bug where the Headspace meditation app silently installs itself on their devices daily. The tech community suspects the issue is an Apple system error, speculating that a test artifact may have accidentally bled into production to trigger the mysterious reinstallations.

Fast16: High-precision software sabotage 5 years before Stuxnet
2026-04-26

A newly identified cyber sabotage framework called Fast16 was patching high-precision calculation software in memory to silently corrupt computational results. Operating as early as 2005, this sophisticated digital attack predates the widely known Stuxnet worm by five years. The discovery highlights the early evolution of stealthy, targeted industrial software sabotage.

Quirks of Human Anatomy
2026-04-26

A reader discussion exploring the quirks of human anatomy debates the misunderstood protective functions of organs like the prostate and tonsils while emphasizing the need for scientific humility when evaluating our biology. The conversation highlights that traits like male nipples simply result from shared developmental blueprints, demonstrating that apparent bodily quirks often serve hidden purposes or represent low-cost evolutionary trade-offs.

Asahi Linux Progress Linux 7.0
2026-04-26

The Asahi Linux project has announced significant progress in its ongoing effort to port the open-source operating system to Apple Silicon Macs. This latest update marks a major milestone in bringing full hardware support and system stability to M-series chips. Developers continue to refine the integration to provide a seamless native Linux experience on Apple hardware.

America's Geothermal Breakthrough
2026-04-26

Enhanced geothermal systems represent a major technological breakthrough poised to significantly expand U.S. clean energy capacity. By unlocking vast underground heat resources, this innovation promises to deliver reliable, round-the-clock renewable power to the national grid.

OpenAI Privacy Filter
2026-04-26

OpenAI has released the Privacy Filter, an open-weight model designed to detect and redact personally identifiable information in text with state-of-the-art accuracy. This new tool provides developers with a highly effective way to automatically scrub sensitive data from text inputs. By making the model open-weight, OpenAI is enabling the broader tech community to integrate and customize these advanced privacy safeguards in their own applications.

Clay PCB Tutorial
2026-04-26

A newly published tutorial explores how makers can fabricate printed circuit boards using wild clay. This innovative DIY method provides a sustainable and accessible alternative to traditional materials for creating custom electronics.

Statecharts: hierarchical state machines
2026-04-26

A recent guide explores the concept of statecharts, also known as hierarchical state machines, by detailing their definitions, benefits, and drawbacks compared to traditional state machines. The article also provides practical examples to help developers understand the differences and effectively implement them in their projects.

Mahjong: A Visual Guide
2026-04-26

A newly released visual guide offers total beginners a quick five-minute tutorial on how to play Mahjong. The resource breaks down essential gameplay mechanics, covering everything from tile identification and wall mechanics to winning hands and turn actions.

Butterflies are in decline across North America, a look at the Western Monarch
2026-04-26

Butterfly populations across North America, particularly the Western Monarch, are experiencing severe declines due to habitat loss, pesticide use, and climate change. Despite these significant environmental threats, conservation experts remain optimistic about the insects' long-term survival and recovery.

EU Age Control: The trojan horse for digital IDs
2026-04-26

Online discussions regarding the EU's age verification mandates clarify that the policy is an explicit stepping stone toward a comprehensive cross-border digital identity system rather than a hidden trojan horse. While some readers defend the utility of mobile ID wallets for international authentication, many emphasize the critical need for privacy-preserving technologies to prevent corporate data harvesting. Ultimately, the debate underscores concerns that widespread digital identity checks could lead to severe privacy violations if businesses are permitted to store unnecessary personal information.

GnuPG – post-quantum crypto landing in mainline
2026-04-26

GnuPG version 2.5.19 introduces the Kyber post-quantum encryption algorithm and SHA256 key fingerprints to secure communications against future quantum computing threats. The transition to quantum-safe encryption is being compared to Y2K, with the underlying migration requiring significant effort despite remaining largely seamless for average users. This update is considered critical to mitigate the risk of previously intercepted encrypted data being compromised once quantum decryption becomes viable.

Magic: The Gathering took me from N2 to Japanese fluency
2026-04-26

A professional in Tokyo shares how playing Magic: The Gathering helped them transition from holding a JLPT N2 language certification to achieving practical fluency in Japanese. By using the card game to practice, they successfully bridged the gap between academic study and confidently managing professional projects in the Japanese workplace.

Show HN: Free textbook on engineering thermodynamics
2026-04-26

The release of a free textbook on engineering thermodynamics has sparked discussions regarding the high costs of traditional textbook publishers and the financial realities of self-publishing. Readers praised the author for democratizing hard science education and sharing print-on-demand profit margins, while also highlighting the ongoing necessity for low-cost physical books in developing regions.