What is the Y Combinator mafia?

The Y Combinator mafia is the network of 4,700 people who studied at Y Combinator and went on to found or lead other companies, including Sightbox, Oisin Biotechnologies, UFORCE Acquired, Founders Pledge, Immunity Project.

Who is in the Y Combinator mafia?

Notable members include Darius "Bubs" Monsef (Sightbox), Matthew Scholz (Oisin Biotechnologies), Oleg Rogynskyy (UFORCE Acquired), Magnus Hambleton (Founders Pledge), Ian (Immunity Project), Guillaume Luccisano (Yuma AI), Danielle Morrill (Firstparty Labs), Ivan Zhou (Decagon), among 4,700 tracked members.

What companies did Y Combinator alumni found?

Companies founded by Y Combinator alumni include Sightbox, Oisin Biotechnologies, UFORCE Acquired, Founders Pledge, Immunity Project, Yuma AI, Firstparty Labs, Decagon, Kanjun, Glider.

The Y Combinator Mafia

4,700 people studied at Y Combinator and went on to found or lead other companies.

Darius "Bubs" MonsefS24Founded Sightbox +3 Matthew ScholzFounded Oisin Biotechnologies +3 Oleg RogynskyyEntrepreneurship/Entrepreneurial StudiesFounded UFORCE Acquired +2 Magnus HambletonFounded Founders Pledge +2 IanFounded Immunity Project +2 Guillaume LuccisanoDid Y Combinator 3 timesFounded Yuma AI +2 Danielle MorrillFounded Firstparty Labs +2 Ivan ZhouW18Founded Decagon +2 Kanjun QiuFounded Kanjun +2 Brandon PatonFounded Glider +2 Khaled HusseinTilt (W12)Founded Tilt +2 Sean GroveFounded Linzumi +2 Andrew LevyFounded Apteligent +2 Weiting LiuYC S07 & S12Founded Everyday.me +2 Russ d'SaSummerFounded Meetyu +2 Gautam JayaramanS06 (Jamglue) and W14 (Rickshaw) and S21 (Greenwork)Founded Onsite Pro +2 João de PaulaEntrepreneurship/Entrepreneurial StudiesFounded Mesmer +2 Jon Miller SchwartzLayer By Layer (S13) & Voodoo Manufacturing (W17)Founded Ultra +2 Max FriefeldNAFounded Ultra +2 Michael WitzFounded Mob Science +2 Val AgostinoFounded Monarch +2 Dillon ErbW15Founded Paperspace +2 James SteinbergFounded OpenShelf +2 Bharat KilaruFounded Verano Health +2 Dmitry StarodubtsevAlumniFounded Creopop +2 Gatumi AliyuFounded Stack Diagnostics +2 Richard WhiteFounded Uservoice +2 Ryan XueW23Founded Andco +2 Jesse BuckinghamW23Founded Vooma +2 Stew FortierW21Founded MassRoots +2 Max AhrensW 24Founded Maihem +2 Don MuirW22 (Arc) + S25 (F2)Founded Arc +2 Josh BuckleyMino Games (YC W11)Founded Mino Games +1 Jinal JhaveriFounded SchoolMint +1 Chris FernandezFellowshipFounded Mindful Health +1 Gleb ChuvpiloAlumFounded Authy +1 Zach WaterfieldFounded Zettlor +1 Josephine LeeYC MIT IAP 2026 Program Grant RecipientFounded Palette Labs +1 Stefano BernardiFounded Unrulycap +1 Sharath Keshava NarayanaFounded Observe.AI +1 Sara DuW20Founded Alloy Automation +1 Paolo PriviteraStartup SchoolFounded 1521 Capital +1 Michael StröckEntrepreneurship/Entrepreneurial StudiesFounded Allocator +1 Julian ShapiroFounded Julian +1 Alex AtallahFounded OpenSea +1 James J BesharaWinter 2012Founded Tilt +1 Eric BlondeelFounded Samos Insurance +1 Adeel YangW18Founded Dryvebox +1 Euwyn PoonFounded 3dot +1 George DeglinFounded Uversity +1 Patrick J. CostelloYC S14Founded Naytev +1 Tonjé Bakang TonjeFounded Moots +1 Armando BiondiBatch S21 FounderFounded AdEspresso +1 Austin OgilvieW15Founded Yhat +1 Kyle MichelsonStreamupFounded Getlabs +1 Matthieu HafemeisterYC W23Founded Concourse +1 Nimit MaruStartups (S12 Batch)Founded Sava +1 Oliver CameronFounded Everyme +1 Sohail PrasadStartupsFounded D/XYZ +1 Tanooj LuthraFounded Elph +1 Oleg KostourW12 / F25Founded AtlasGrid +1 Anton KrutianskyFounded AtlasGrid +1 Brian NoguchiS12Founded Smartcuts +1 Aamir PoonawallaTapToLearn - yCombinator Class of W2012Founded Understudy Labs +1 Henry LiuW12Founded Glider +1 Peter DelahuntyFounded 99dresses +1 Min Ming LoWinter 2012Founded Hyperink +1 Lawrence GentilelloFounderFounded Optery +1 Sasha OrloffW'12 BatchFounded LendUp +1 Akshay DodejaFounded Terminal49 +1 Pradeep ElankumaranS16Founded jo +1 Darren NixS11 and S15Founded Interviewed +1 Srini PanguluriFounded Project Wedding +1 Peter ClarkFounded Journey +1 Jason CorwinFounded Safely Finance +1 Leah CulverConvoreFounded Breaker +1 Ryan BednarW11Founded RankScience +1 Gabe KrambsFounded Compound +1 Daniel KivatinosEntrepreneurship/Entrepreneurial StudiesFounded loopfour +1 Ray GrieselhuberAcceleratorFounded Functionize +1 Rudy AdlerStartup IncubatorFounded Wealthsimple +1 Brett HuneycuttFounded Wealthsimple +1 David TranS10Founded Flow Club +1 Rod EbrahimiSummer 2010 BatchFounded Ready For Zero +1 Vishwas PrabhakaraStartupsFounded Fanvibe +1 Arthur ChangS10Founded Priime +1 Joe PestroFounded Priime +1 Denis MarsS16 - ProxyFounded Proxy +1 Steve HeffernanYC W10 - ZencoderFounded Mux +1 Dane HurtubiseSpoken (S21)Founded Spoken +1 Suhail DoshiStarting a company (again)Founded Playground +1 Tim TrefrenFounded Recheck +1 Henry LiuFounded Glide +1 Arun GuptaFounded Wakemate +1 Savraj SinghS07 W09Founded ContestMachine +1 Luke GroesbeckFounded Foundation +1

+ 4,604 more

Frequently asked questions

What is the Y Combinator mafia?: The Y Combinator mafia is the network of 4,700 people who studied at Y Combinator and went on to found or lead other companies, including Sightbox, Oisin Biotechnologies, UFORCE Acquired, Founders Pledge, Immunity Project.
Who is in the Y Combinator mafia?: Notable members include Darius "Bubs" Monsef (Sightbox), Matthew Scholz (Oisin Biotechnologies), Oleg Rogynskyy (UFORCE Acquired), Magnus Hambleton (Founders Pledge), Ian (Immunity Project), Guillaume Luccisano (Yuma AI), Danielle Morrill (Firstparty Labs), Ivan Zhou (Decagon), among 4,700 tracked members.
What companies did Y Combinator alumni found?: Companies founded by Y Combinator alumni include Sightbox, Oisin Biotechnologies, UFORCE Acquired, Founders Pledge, Immunity Project, Yuma AI, Firstparty Labs, Decagon, Kanjun, Glider.