Category:Y Combinator alumni

Y Combinator is a startup accelerator that has funded companies in fixed batches since its first cohort in the summer of 2005, taking each group through a few months of mentorship and seed funding before a demo day for investors. It appears on this wiki as a career waypoint rather than an employer: almost everyone here passed through as a founder, and a handful returned later as partners. The membership is weighted heavily toward the batches of the last two years, thinning out into a much smaller and much older layer that runs back to the accelerator's first summer.

The earliest members of this category arrived before the accelerator model was established. Steve Huffman and Alexis Ohanian applied out of the University of Virginia in 2005 with a mobile food-ordering idea called My Mobile Menu; Paul Graham rejected it and redirected them, and what they built instead was Reddit, which entered the inaugural batch that summer. Sam Altman was in the same cohort with Loopt, a geolocation app he co-founded at nineteen. Justin Kan and Emmett Shear came through with Justin.tv, the lifecasting experiment that became Twitch.

The batches that followed produced most of the names the accelerator is now known for. John Collison was seventeen when Auctomatic, built with his brother Patrick, was accepted; the connections made there preceded Stripe by several years. Drew Houston took Dropbox through after co-founding it with a fellow MIT student. Brian Chesky and Nathan Blecharczyk entered in early 2009, having funded Airbnb in the interim by selling novelty election cereal boxes. Apoorva Mehta applied with Instacart and used the program to rework the business model before raising. Tomer London and his co-founders brought ZenPayroll, later Gusto, through on what was reported at the time as one of the accelerator's largest seed rounds.

An unusual feature of this roster is how many of its members returned to the other side of the table. Sam Altman began working with the accelerator part-time in 2011, was selected by Paul Graham to succeed him as president in 2014, and held the role until 2019, when he left to run OpenAI full-time. Emmett Shear was appointed a part-time partner in 2011, the same year Twitch launched, and held both roles at once. Justin Kan served as a partner until 2017, when he left to start Atrium. Alexis Ohanian mentored early-stage companies as a partner at the accelerator that had funded Reddit. That loop, from batch founder to batch selector, is a large part of why this category behaves less like an alumni list and more like a network.

The bulk of the membership comes from cohorts running roughly from Winter 2024 to Fall 2025, and it reads very differently from the layer above it. These are almost all technical co-founders, most of them building agent tooling, developer infrastructure, or vertical automation, and most of them based in San Francisco. Adhityaa Chandrasekar and Sachin Sridhar came through with Subtrace, a network tracer for backend infrastructure. Caitlin Leksana and Timmy Galvin built Fazeshift for accounts receivable. Ansh Gupta and Adarsh Ambati brought Haleum. Stef Crum took Reditus Space, a reusable satellite company, through from Atlanta rather than the Bay Area. Jess Li and Ian Dardani came through with Biocartesian, and Weronika Slesak with an antibiotics company run out of Oxford.

The entry routes into these batches are worth noting because they are not uniform. Raveen Kariyawasam and Ege Kaan Duman are both Rhodes Scholars and both co-founded the same company. Maximilian Hofer competed in European GT racing before founding a technology company. Arlan Rakhmetzhanov left high school in Kazakhstan to build his. The batch system is the only thing this group has in common, which is the argument for keeping them under one heading.

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