Fundraising Fox

Justin Sun

Founder

Founder at Capy

San Francisco Bay Area

FoundedCapy Β· YC

About

Justin Sun is cofounder of Capy, a development environment that coordinates multiple AI agents to write and ship software.

LinkedIn β†—X / Twitter β†—
Latest on 𝕏

justin @justinsunyt

https://t.co/DsAGvAB4Ng

Jul 30, 2026 Β· β™₯ 3

justin @justinsunyt

We signed the Open Weights letter. Every day, Capy routes thousands of software engineering tasks across closed and open models. Increasingly, our customers are no longer relying on a singular model, but rather an ensemble - each suited for their task and even shaped by their https://t.co/otMpUme9CI

Jul 30, 2026 Β· β™₯ 47 Β· ⇄ 3

justin @justinsunyt

actually, all three beliefs are right the less harness, the better: true for frontier models working on isolated single shot tasks. mini-swe-agent outperforms codex and claude on coding benchmarks with a single bash tool, while being significantly cheaper. for tasks that don’t https://t.co/SOUybwdnq6

Jul 29, 2026 Β· β™₯ 97 Β· ⇄ 10

Founder at CapyYC F24

Intro paths

YC

Justin went through Y Combinator (Fall 2024) β€” any YC alum in your network can reach them through the YC community.

GP

Their group partner at YC was David Lieb, General Partner at Y Combinator β€” the partner who ran Capy's batch and knows the company first-hand. YC profile β†—

β†’

In turn, Justin can intro founders to Capy's investors below.

Capy's investors Β· 2

CRV (Charles River Ventures)Y Combinator

Co-founders at Capy

NSNalin Semwal
Nalin SemwalFounder
MO
Mitsuo OkadaExecutive Officer, Director

Experience

  1. CapyCo-Foundercurrent2024 β€” presentSan Francisco Bay Area
  2. MultiOnEngineer2024
  3. Penn LabsEngineer2023 β€” 2024
  4. Penn Electric RacingEngineer2022 β€” 2024
  5. VEX Robotics Team 62Captain2018 β€” 2022

Education

  1. Y CombinatorF24
  2. Jerome Fisher M&T Program
  3. The Wharton SchoolBachelor of Science in Economics (BS), Entrepreneurship/Entrepreneurial Studies
  4. University of PennsylvaniaBachelor of Science in Engineering (BSE), Computer Science
  5. Harvard-Westlake SchoolHigh School Diploma2018 β€” 2022
  6. Viewpoint SchoolMiddle School Diploma2016 β€” 2018

Founder mafias

Y Combinator mafia8,668

Also came through, then founded or led a company.

Sam AltmanPresidentFounded LooptFred EhrsamYC Summer 2012Founded CoinbaseMatt HuangYC Winter 2011Founded HotspotsTrae StephensYC Winter 2022Founded PursuitDelian AsparouhovYC Summer 2014Founded Nightingale +1Justin KanYC Winter 2018Founded Rye +3

+ 8,661 more

University of Pennsylvania mafia157

Also came through, then founded or led a company.

Eric HeilBSEFounded Ladderbio +1Scott Wolf, MDBAFounded Aerin Medical +1Abhijeet DwivediMastersFounded Central +1Ross ChaninB.A.Founded Reputation Com +1Alexander BelangerBachelor's degreeFounded Hatchet +1Brianna LinMathematics and Computer ScienceFounded Copperlane +1

+ 150 more

The Wharton School mafia154

Also came through, then founded or led a company.

Jack AbrahamBachelors of Science in Economics *Dropped outFounded Sauron +5Eric HeilMBAFounded Ladderbio +1Ankur JainBachelor of Science (BS)Founded Rhino +1Nimit MaruMBAFounded Sava +1Allan (Amnon) FischMBAFounded Moonshot Brands +1Max MergenthalerWharton's Entrepreneurship SpecializationFounded Nixtla +1

+ 147 more

Jerome Fisher M&T Program mafia17

Also came through, then founded or led a company.

Brianna LinComputer ScienceFounded Copperlane +1Parth ChopraFounded LagunaDaniel BessonovBachelor of Science - BSFounded AvoraSam OshayWharton-Engineering Joint Degree ProgramFounded RecurrencyKunal GargBachelor's degreeFounded BracketYonah MannWhartonFounded Luca

+ 10 more

Harvard-Westlake School mafia8

Also came through, then founded or led a company.

IanHigh SchoolFounded Zynga +1Spencer RascoffHigh School degreeFounded House Whisper +1Ian CinnamonHigh SchoolFounded Immunity Project +1Ian CinnamonHigh SchoolFounded ZyngaHamilton ChanFounded PayDragonJacob TuckerDiplomaFounded Sonatoria

+ 1 more

Same school

Also attended Y Combinator2,000

Leo LuInvestor at Foundation CapitalMaroof AhmedFounder at Octopus VenturesJustin SwartPartner at Bitkraft Esports VenturesVictor SantosVictor Scout at One Way VenturesSwapnil JainCEO, Observe.AI at EMERGENT VENTURESChase AdamPartner at Very Serious Ventures

+ 1,994 more

Also attended Jerome Fisher M&T Program29

Joe TsaiPartner at Mucker CapitalAlex DollInvestor at Ten ElevenManeesha GhiyaManaging Partner at FemHealth VenturesSophia AfrickInvestor at Long Ridge Equity PartnersKunal BahlCo-Founder at Titan CapitalParth ChopraPartner at Bain Capital Crypto

+ 23 more

Also attended University of Pennsylvania764

Dasha MaggioPartner at Felicis Ventures, writer on venture capital and founder psychologyNancy WangInvestor at Felicis VenturesEghosa OmoiguiFounder and Managing General Partner at EchoVC PartnersAkshat GoenkaInvestor at Moonfire VenturesJames KuklinskiInvestor at Spark CapitalKerry KilleenAssociate General Counsel at Revolution

+ 758 more

Also attended Harvard-Westlake School33

Johnny HooperAssociate at March Capital PartnersNick PenskeInvestment Team at 8VCAlyssa TsenterSenior Associate at Flare Capital PartnersJohn CopsesSenior Associate at CAVU Consumer PartnersIra EhrenpreisFounder and Managing Partner at DBL PartnersConor CookPlatform Manager at Comcast Ventures

+ 27 more

Shared employers

Also worked at Capy1

Nalin SemwalFounder at Capy

Also worked at MultiOn5

Mark KimInvestor at Samsung NextMei Z.General Partner at Alloy FundDaryl BudimanFounder at ZeroframeAnirudh RamprasadFounder at ZeroframeNalin SemwalFounder at Capy

Also worked at Penn Electric Racing4

David Zhi LuoZhangFounder at Bronco AIJason KaufmannFounder at Maritime FusionDaichi HiraokaFounder at KorsoMartin PanFounder at Korso