Watch the DoorDash team's YC application video

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

In one of Paul Graham’s essays on his website, he took the time to explain how and why he and his cofounders (including his girlfriend at the time, and now wife, Jessica Livingston), came up with the idea of and eventually created Y Combinator.

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.

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.

Visualize where the first batch of founders from the famous startup accelerator Y Combinator are now.

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.

‘Demo days’ are when founders at Y Combinator pitch their startup ideas

Investors sit in the audience, waiting to hear what this season’s batch of YC founders have cooked up. YC argues that going through the process of a demo day can help founders get a better understanding of their startup themselves.

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.

Listen to a podcast episode where Y Combinator CEO Gary Tan explains why YC tends to outperform many other Silicon Valley startup accelerators.

Y Combinator, the startup accelerator, gets its name from the 'Y combinator' computer science concept.

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.

For Reddit's founders, the company's early days included choosing a dinner with Y Combinator's Paul Graham over a spring break trip, a $10M Condé Nast acquisition, and other pivotal moments.

Explore the schedule of a three-month YC batch

During the three months that founders accepted into Y Combinator spend on YC’s California campus, they receive mentorship from YC partners, networking opportunities, and, overall, a ton of time to build and scale their companies.

Sam Altman gave his first-ever startup pitch after dropping out of Stanford

He dropped out of Stanford to start Loopt, which sold in 2012 for $43.4M. You can watch his first-ever startup pitch in a video.

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 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.

Delivery apps have realigned the restaurant industry

As delivery apps like Grubhub and DoorDash became popularity, traditional dine-in restaurants have adapted to become more accommodating. In this thinkpiece for the Atlantic, Ellen Cushing argues that it's both changed the kind of food being made and realigned our very notion of a restaurant. (Some readers may experience a paywall.)

Many startup founders pull out-of-the-box stunts to get their businesses off the ground.

Dive deep into the numbers that shape each YC deal

Y Combinator invests $500K into each company in any given batch. $125K of that investment converts into a fixed 7% in ownership of the startup, and the other $375K is invested on something called an uncapped MFN safe. YC explains what that means and more terms of the deal in a detailed article on their website

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.

Read an article about Uber's origin story, which starts back in 2009 when its cofounders tried to catch a cab during a Paris snowstorm without much luck.

Mark Zuckerberg credits some of Facebook's success to constant evolution

Before becoming the head of OpenAI, Sam Altman was the president of Y Combinator—a startup accelerator company that supported companies like Airbnb, DoorDash, and Coinbase. In 2016, Altman interviewed Zuckerberg about creating Facebook and its growth over time. Zuckerberg said that, unlike other companies (think: CourseMatch), Facebook kept growing and adding new features, which prevented the app from becoming obsolete.

Understanding TikTok-owner ByteDance's business model

ByteDance has ridden TikTok's major success to become the world's most valuable startup. This deep dive showcases some of the company's smartest moves and tactics, and where it's headed next.

TikTok CEO Shou Zi Chew on its future

TikTok CEO Shou Zi Chew dives into how the trendsetting video app and cultural phenomenon works, from what distinguishes its algorithm and drives viral videos, to the challenges of content moderation and digital addiction in this wide-ranging conversation with the head of TED, Chris Anderson.

A timeline and visuals on TikTok's rapid growth

The app that would become TikTok is known as Douyin in China, and this article recounts its history, acquisition of rival Musical.ly, and rebranding ahead of its lightning growth. One visualization shows how quickly TikTok reached 1B users.

Robinhood's mission of democratizing finance included its IPO

In 2021, investing app Robinhood went public—and decided to go about its IPO process differently. Unlike other companies, it opened up its IPO for the general public to purchase right away. A podcast episode explains what made Robinhood's IPO so unique prior to its launch date.

See design app Canva's original pitch deck for investors

The full story of WeWork, one of the most dramatic startup journeys of all time

WeWork has been through a lot since the office space company was founded as a startup in 2010. From its failed IPO in 2019, to the various leadership antics of its founder, Adam Neumann (some have claimed that he acted like a cult leader at times), to how it navigated remote work trends during the pandemic, this video tells the full story of WeWork's growth, failures, and more.

Startup accelerators that include more training activities, such as pitch competitions, tend to have better long-term success rates

That's according to a new study from Wharton. Y-Combinator, perhaps the most famous startup accelerator, currently has 16 alumni companies trading on the public market. But not every entrepreneur who joins a startup accelerator makes it big.

YouTube was acquired by Google for $1.65B in stock during its second year

In 2006, Google acquired YouTube for $1.65B, only two years after its launch. Sequoia Capital, one of Silicon Valley's best-known venture firms, was an early investor in the streaming video platform, seeing it as the next step in the evolution of user-generated content that flourished online during the mid-2000s.

87% of the startups in Y Combinator’s Fall 2025 batch were AI companies

Y Combinator also recently increased its number of cohorts or “batches” per year from two to four. Its leaders cited artificial intelligence’s rise as a reason for the increase.

Bumble went public with an IPO in 2021

That year, Bumble Founder Whitney Wolfe Herd became the youngest female CEO to ever take a company public. The company pivoted during the 2020 COVID-19 pandemic lockdowns, focusing its marketing strategy on promoting social-distanced dating and its video chat features.

Listen to a podcast episode that explains how the Chinese discount e-commerce retailer Temu became one of the most downloaded apps in the US.

Andreessen Horowitz is among the most well-known venture capital firms

Also known as a16z, the firm has invested in companies such as Airbnb, Facebook, and Lyft since its founding in 2009. A podcast episode offers a deep dive into how the firm got started and became the industry disruptor it is today.

Yahoo acquired Paul Graham's former startup Viaweb in 1998

Viaweb was the web app tech startup that Paul Graham, Robert Morris, and Trevor Blackwell cofounded before they started Y Combinator. The company sold for $49M and Viaweb was rebranded as the Yahoo Store.

Uber's first investors included StumbleUpon founder Garrett Camp

In 2010 when Uber went out to raise money, prominent investors including Mark Cuban and Gary Vaynerchuk passed. Vaynerchuk actually said no twice.

Robinhood's pivot from everyday investors to hyperactive traders

The platform was conceived as a hub for first-time investors looking to get into trading. After criticism in 2021, the company pivoted to focus on more regular, daily traders, among whom the company's CEO has now become a cult hero.

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.

7 prominent investors rejected Airbnb in its early days

Airbnb is arguably known as one of the most successful startup stories of all time. But back in 2008, many prominent investors rejected their pitch when they went out to raise money—and Airbnb's founder still has the rejection emails to prove it.

The dot-com boom made Mark Cuban a billionaire

Cuban co-founded AudioNet with Todd Wagner in 1995 before it became Broadcast.com—a web app that allowed people to listen to sports commentary on their computers if they couldn't watch a game. In 1999, Yahoo bought Broadcast.com for $5.7B. By the time the market crashed, Cuban had already sold most of his stock in the company and had become a billionaire.

WellHub is a startup serving roughly 4 million people in 11 countries, providing broad wellness benefits to employees

Valued at $2.4B in 2025, the company helps workers get gym access and meditation apps, in addition to basic healthcare. Listen to the founder of the company, Cesar Cevalho, explain how he scaled the company with Jeff Berman.

Three AI startup founders broke the record for the youngest self-made billionaire previously set by Mark Zuckerberg

Mark Zuckerberg became the youngest self-made billionaire in 2006 at 23 years old when Facebook held its initial public offering. In January of 2026, three AI startup founders—Brendan Foody, Adarsh Hiremath, and Surya Midha—broke Zuckerberg's record and became billionaires at 22 years old.

Find out what it's like to work in the gig economy

If you’re thinking about being a gig worker—for example, an Airbnb host, Lyft driver, or DoorDash delivery person—keep this article in mind before you start. This article outlines particular concepts prospective gig workers should think about before signing up for gig work, such as upfront costs and budgeting for taxes.

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.

Some companies like to make their IPO day antics unique.

An article details some of the wildest bell-ringing day stunts in recent history, from Clifford the Big Red Dog ringing the opening bell to one company's employees roasting marshmallows in a campfire on Wall Street as it went public.

Why TikTok loves fast-casual restaurant Chili's

The company noticed TikTokers posting enthusiastically about its food and began partnering with creators on the platform. The videos include mukbangs, a South Korean trend in which users eat a massive amount of food, and #cheesepulls, where Chili's mozzarella sticks are stretched to their limits.

Startups follow a 'minimum viable product' strategy to determine demand

Michael Seibel, group partner for startup incubator Y Combinator, explains how to build a minimum viable product (also known as an MVP) for any startup idea. Using real companies that experienced the Y Combinator program as examples, he walks through how to determine an MVP feature set, how to present an MVP to potential investors, and more.

Dating app Bumble Founder Whitney Wolfe Herd is considered the youngest self-made female billionaire.

YouTube's first video was grainy video of co-founder Jawed Karim at the zoo

Some 500 hours of content are posted to YouTube every minute. The video at the beginning of that massive growing stream of content is this one—"Me at the Zoo." Uploaded in April 2005 by YouTube co-founder Jawed Karim, it shows him at the San Diego Zoo talking about elephants.

Youtube, explained

YouTube began as a quirky site where users uploaded funny, random videos—a do-it-yourself television service. Today, it’s a global media powerhouse and home to everything from movie trailers to video podcasts, livestreams, and much more. Want to learn more about the streaming giant? Check out our 5-minute explainer here.

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