Y Combinator companies

Quora is an American social question-and-answer website and online knowledge market headquartered in Mountain View, California. It was founded on June 25, 2009, and made available to the public on June 21, 2010. Users can post questions, answer questions, and comment on answers that have been submitted by other users.

Airbnb, Inc. ( , an abbreviation of its original name, "Airbed and Breakfast") is an American company operating an online marketplace for short-and-long-term homestays, experiences and services in various countries and regions. It acts as a broker and charges a commission from each booking. Airbnb was founded in 2008 by Brian Chesky, Nathan Blecharczyk, and Joe Gebbia.

Dropbox is a file hosting service operated by the American company Dropbox, Inc., headquartered in San Francisco, California, that offers cloud storage, file synchronization, personal cloud, and client software. Dropbox was founded in 2007 by MIT students Drew Houston and Arash Ferdowsi as a startup company, with initial funding from seed accelerator Y Combinator.

Coinbase Global, Inc. is an American cryptocurrency exchange. It was founded in 2012 by Brian Armstrong and Fred Ehrsam. Coinbase has over 100 million users, and is the largest U.S. based cryptocurrency exchange as well as the world's biggest bitcoin custodian, as of 2024. The company operates in more than 100 countries and holds nearly US$516 billion in assets, including nearly 12 percent of all bitcoin in existence and 11 percent of all staked Ether.

9gag (stylized as 9GAG) is an online platform and social media website based in Hong Kong, which allows its users to upload and share user-generated content or other content from external social media websites. Since the platform for collections of Internet memes was launched on April 11, 2008, it has grown in popularity across social media such as Facebook, Twitter, and Instagram.

Scribd Inc. (pronounced ) is an American media company that operates four primary platforms: Scribd, Everand, SlideShare, and Fable. Scribd is a digital document library that hosts over 240 million documents. Everand is a digital content subscription service offering a wide selection of ebooks, audiobooks, magazines, podcasts, and sheet music. SlideShare is an online platform featuring 25 million presentations uploaded by subject matter experts.

Irish-American payment technology company

Disqus () is an American blog comment hosting service for websites and online communities that use a networked platform. The company's platform includes various features, such as social integration, social networking, user profiles, spam and moderation tools, analytics, email notifications, and mobile commenting. It was founded in 2007 by Daniel Ha and Jason Yan as a Y Combinator startup.

DoorDash, Inc. is an American company operating online food ordering and food delivery. It trades under the symbol DASH. With a 56% market share, DoorDash is the largest food delivery platform in the United States. It also has a 60% market share in the convenience delivery category. As of December 31, 2020, the platform was used by 450,000 merchants, 20 million consumers, and had over one million delivery couriers.

Weebly, a subsidiary of Block, Inc., is an American web hosting and web development company based in San Francisco, California. Founded in 2006 by David Rusenko, Chris Fanini, and Dan Veltri, the company offers WYSIWYG website creation services and hosting. David Rusenko served as the Chief Executive Officer, Chris Fanini as the Chief Technology Officer, and Dan Veltri as the Chief Product Officer.

OpenSea is an American digital asset platform founded in 2017 by Devin Finzer and Alex Atallah. It facilitates the trading of cryptocurrencies and the buying, selling, and minting of non-fungible tokens (NFTs) across a range of blockchains. Headquartered in Miami, OpenSea supports fixed-price sales and auctions for digital assets including artwork, music, gaming items, and domain names.

Heroku is a cloud platform as a service (PaaS) supporting several programming languages. As one of the first cloud platforms, Heroku has been in development since June 2007, when it supported only the Ruby programming language, but now also supports Java, Node.js, Scala, Clojure, Python, PHP, and Go. For this reason, Heroku is said to be a polyglot platform as it has features for a developer to build, run and scale applications in a similar manner across most of these languages. Heroku was acquired by Salesforce in 2010 for $212 million.

social news website

Justin.tv was a website created by Justin Kan, Emmett Shear, Michael Seibel, and Kyle Vogt in 2007 to allow anyone to broadcast video online. Justin.tv user accounts were called "channels", like those on YouTube, and users were encouraged to broadcast a wide variety of user-generated live video content, called "broadcasts".

150px|thumb|The Instacart logo is a simplified carrot. Logo since 2022.

Songkick is a concert discovery service owned by Warner Music Group. The service allows users to search for upcoming concert events in their area, and also track individual artists to receive notifications of upcoming shows in their area. It also provides services for artist teams to manage and promote tour dates globally.

product discovery website

Zapier ( ) is an American software company that provides a platform for business process automation and application integration services. Its platform allows users to move data across web-based applications, automate tasks, and incorporate artificial intelligence (AI) into workflows and systems. The company was founded in 2011, and officially launched in 2012 as part of the Y Combinator startup accelerator program. As a low-code/no-code platform, Zapier is intended for users with minimal to moderate technical knowledge.

self-driving car company

global non-profit dedicated to inspiring women to excel in technology careers

Algolia is a French proprietary search-as-a-service platform, with its headquarters in San Francisco and offices in Paris and London. Its main product is a web search platform for individual websites.

online therapy website

Loopt, Inc. was an American company based in Mountain View, California, which provided a service for smartphone users to share their location selectively with other people. The company entered partnerships with major U.S. mobile phone carriers including Verizon Wireless and Sprint-Nextel to include Loopt on their handsets and the service reached 4 million registered users in July 2010. In addition to its core features, users also had the ability to integrate Loopt with other social networks, including Facebook and Twitter.

Unbabel is an artificial intelligence-powered human translation platform. The company has headquarters in Lisbon, Portugal, and San Francisco, California. It has been owned by American translation and language services company TransPerfect since August 2025.