Y Combinator was founded in 2005 to bridge gaps between founders and investors

Y Combinator Cofounder Jessica Livingston once interviewed her husband and cofounder, Paul Graham

Two of Y Combinator’s cofounders, Jessica Livingston and Paul Graham, were in a romantic relationship before they started the accelerator. They later married, and much later, Livingston started a podcast. In an episode of her podcast, Livingston and her cohost interview Graham about the beginning of YC and more.

Read Paul Graham’s initial post announcing YC’s first batch

In March 2005, Y Combinator cofounder Paul Graham announced the program that would become Y Combinator on his website.

Y Combinator cofounder Paul Graham keeps a public archive of his insightful essays

In addition to cofounding Y Combinator and other companies before it, Paul Graham is a prolific writer and artist. He chronicled many of his thoughts while building Y Combinator in a series of dozens of candid essays, all of which you can read in an online archive.

Y Combinator takes its name from a computer science concept

Y Combinator, the startup accelerator, gets its name from the “Y combinator” computer science concept. Specifically, something called a “Y combinator” in computer science is a function that runs programs, just like the Y Combinator startup accelerator runs a program that helps grow startups.

YC was partly inspired by an investor named Julian Weber

Y Combinator Cofounder Paul Graham’s former professor’s husband Julian Weber provided $10K in seed funding to Graham’s previous startup, Viaweb in its early days. In exchange, Weber received 10% of the company. Weber’s involvement inspired Graham to start a program where investors were more involved with the companies they contributed seed funding to.

Y Combinator tends to outperform many other Silicon Valley startup accelerators

In a podcast episode, Garry Tan—CEO of startup accelerator Y Combinator—speaks about how YC has a better track record than the rest of Silicon Valley at placing bets on startups. Learn how Tan earned his first million dollars, as well as lessons from other successful businesspeople, including Y Combinator’s Paul Graham.

Y Combinator changed the way startups around the world are built

Many of the philosophies that the leaders of Y Combinator have infused into the program’s portfolio companies have become the playbook for building the next big thing, such as its focus on founder personality and more.

CEO Gary Tan explains Y Combinators guiding philosophy

Hear YC President and CEO Garry Tan talk about why he values earnesty and excellent communication skills in YC founders, his thoughts on AI, and more in this unexpectedly deep and in-depth interview.

The Y Combinator startup directory includes every company YC has funded

The startup accelerator has funded more than 5,000 companies over the years. This YC-specific search engine lets you look up any company to find out if it's a YC alum.

Where are the first batch of YC founders now?

Reddit was one of the companies in Y Combinator’s first batch. While OpenAI wasn’t among the companies started at YC, Sam Altman, who would later become the AI company’s CEO, had a different company called Loopt in the first batch.

Stanford’s ‘How to Start a Startup’ series

Stanford’s archive of lectures about creating a startup includes advice from Y Combinator notables such as former YC president and OpenAI CEO Sam Altman and YC Cofounder Paul Graham.

Y Combinator has a roughly 1% acceptance rate

That’s lower than the most elite universities and colleges in the world—but insiders have some tips about how applicants can have the best shot of being accepted to the selective startup accelerator.

'Founder mode' is the idea that startup founders should take a hands-on approach to running their businesses

In 2024, Y Combinator cofounder Paul Graham popularized the idea of "founder mode" when he wrote a viral manifesto in response to a talk that Airbnb CEO Brian Chesky gave about leadership styles. Graham positioned the concept of founder mode as the opposite of manager mode—when founders hire executives and middle managers to run their companies and make decisions that Graham says are better left to founders.

Startup accelerators offer mentorship and seed funding in exchange for equity

Those programs, such as Y Combinator and Techstars, not only offer expert advice to founders, but also seed funding in exchange for equity. The goal is to help young startups learn from successful companies, making it more likely they attract venture capital.

Peter Thiel and Elon Musk formed PayPal after merging two dot-com companies

Elon Musk cofounded "X.com," an online banking service, in 1999 with the idea that the web would become a financial repository as internet access expanded and became ingrained in daily life. Peter Thiel cofounded "Confinity" as a digital security service that morphed into a payments system. In 2000, the two merged to form PayPal, and in 2002, they sold PayPal to eBay for $1.5B.

How venture capital firms came to be

The venture capital firm that kickstarted an industry.

ChatGPT was conceived over dinner at a Silicon Valley hotel

A guest list of tech leaders, including Elon Musk, Peter Thiel, and LinkedIn cofounder Reid Hoffman, met to discuss how to counter Google's efforts to create human-level cognition systems. The group initially committed a reported $1B to launch the effort.

YouTube began as a quirky site invented by former PayPal employees

In February 2005, YouTube was launched by Steve Chen, Chad Hurley, and Jawed Karim. Their idea was to build a platform to support the convenient sharing of videos online, a relatively novel idea in the days of cable TV and early social media.

Bumble's origin story includes a Russian billionaire, a Tinder cofounder, and a private jet

Whitney Wolfe Herd founded Bumble as a female-focused alternative to Tinder in 2014, inspired by the harassment she saw women on Tinder facing when she worked there. Instead of both parties being able to message each other first, on Bumble, women had to make the first move.

Legendary venture capitalist Peter Thiel once wrote that 'competition is for losers'

With Peter Thiel's "Monopoly Theory," the Founders Fund partner argued that investing in companies that create new categories, rather than those that compete with other businesses in existing ones, is a best practice in venture capital.

The dot-com bubble burst in the early 2000s

If you’ve heard of companies like Google and Yahoo, you’re already partially familiar with the dot-com bubble: a period from roughly 1995 to 2001, when internet companies were the hottest thing in venture capital. The “bubble” part of the term refers to the industry’s eventual implosion.

Read about Palantir's early days—from a Stanford University dorm to an investment from the CIA

Palantir was originally founded after the 9/11 attacks as a private-sector solution to the government's growing need for advanced intelligence. One of its earliest investors was In-Q-Tel, the CIA's non-profit venture capital firm.

The early success of Facebook made Mark Zuckerberg a college campus celebrity

Within 24 hours of launching in 2004, more than 1,200 Harvard students signed up to the platform, which quickly expanded to other Ivy League and Boston-area schools within months. By year's end, Zuckerberg left Harvard to run the company in California.

Venture capital is a form of funding provided to early-stage companies with high growth potential, typically in exchange for an equity (or ownership) stake

See the small apartment WeWork founder Adam Neumann lived in before he was a billionaire

WeWork CEO Adam Neumann used to share a relatively small apartment in New York City with his wife before he became a billionaire off of WeWork. At one point, the apartment rented for $3K per month.

The name 'Silicon Valley' arose from the founding of Shockley Semiconductor Laboratory in Fairchild Semiconductor in 1956-57, founded near Stanford University in Palo Alto

Computer scientists first started trying to optimize dating using computers in the 1950s

Although early dating sites like Match.com weren't launched until the 1990s, the history of dating apps dates arguably back to the mid-1900s when computer scientists used IBM computers to solve matchmaking and compatibility problems.

A Yale student wrote a profound essay about the consulting industry's influence on elite college students that was published in a book of her writing after she died in a post-graduation car accident.

Warren Buffett's former professor Benjamin Graham is known as the 'father of value investing,' a strategy in which investors seek to buy stocks trading below their intrinsic worth.

In 2025, four executives from large tech companies were given positions in the US Army Reserves—including Palantir Chief Technology Officer Shyam Sankar, which reinforced Palantir's ties with the US military and its role as a leading defense partner.

How Amazon operates a 'flywheel' business model, a self-reinforcing cycle that drives continuous growth

English mathematician Ada Lovelace wrote the first computer algorithm a century before computers existed and hypothesized that computing devices would one day be able to compose music—foreseeing the generative AI systems of today.

While the first exchange-traded fund (a 'basket' of different assets that can be bought and sold on a stock exchange) in the US only launched in 1993, the global ETF market has grown to more than $10T in the short time since.

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

Children are now three times more likely to say they want to be a YouTuber when they grow up than an astronaut, with some even attending 'YouTube camps' that teach kids how to create content for the platform.

US housing costs have risen by roughly 175% between 1991 and 2026—but a growing number of Gen Zers are becoming homeowners anyway. In 2025, 4% of homebuyers were Gen Z, up from 3% the year before.

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

Legendary architect Frank Lloyd Wright designed the SC Johnson headquarters in Wisconsin, aiming to make a cathedral-like workplace

The Brothers Grimm were lawyers before they were storytellers, and became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.

This site reaches millions of visitors who are tired of AI chatbots and seeking human connection. Pretend to be an AI chatbot and ask questions, provide answers, and draw for people in real time.

Up to a million Girl Scouts sell about 200 million cookie boxes every spring, generating $800 million, largely because refusing a child is frowned upon

Jimmy Carter signed a 1978 bill that legalized home brewing, a move credited with kick-starting the craft beer industry.

American dance legend Martha Graham, sometimes called 'the Picasso of dance,' refused to perform at the 1936 Olympics in Berlin and conceived the piece 'Chronicle' in response to the experience.

The rivalry between Alexander Hamilton and Thomas Jefferson centered on federalism—the question of how much power the federal government should hold relative to the states.

Search a massive database of over 4 decades of clues from the TV quiz show 'Jeopardy!'

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

The first steps to rebuilding your credit score include getting to know exactly what's on your credit report and figuring out how far you are from the '700 club,' or 'good score' range.