Jack Mastrangelo
FounderFounder at Cobblestone
New York, New York, United States
FoundedCobblestone · YC
Find your path to Jack
550 people in our graph share verified history with Jack — schools, employers, funds. One of them is your warm intro.
About
Jack Mastrangelo is a cofounder of Cobblestone who previously worked as a software engineer at Ramp and Facebook.
Founder at CobblestoneYC W23
Intro paths
Jack went through Y Combinator (Winter 2023) — any YC alum in your network can reach them through the YC community.
Their group partner at YC was Jared Friedman, YC Group Partner — the partner who ran Cobblestone's batch and knows the company first-hand. YC profile ↗
In turn, Jack can intro founders to Cobblestone's investors below.
Cobblestone's investors · 2
Co-founders at Cobblestone
Experience
- MoabDirector of Engineeringcurrent2026 — presentNew York, NY
- 100Advisorcurrent2025 — present
- CrosbyFounding Engineer2025 — 2026New York City Metropolitan Area
- CobblestoneCo-Founder, CTO (YC W23, Acquired by 100)2023 — 2025New York City Metropolitan Area
- RampSenior Software Engineer2022New York City Metropolitan Area
- RampSoftware Engineer2021 — 2022New York, United States
- FacebookSoftware Engineer2020 — 2021New York, United States
- GatherlySoftware Engineer2020Atlanta, Georgia, United States
- Northeastern UniversityFundamentals of Computer Science Teaching Assistant2017 — 2020Greater Boston Area
- GoogleSoftware Engineer Intern2019Irvine, California
- FacebookSoftware Engineer Intern2019Menlo Park, California
- PlacePassFull-stack Developer Co-op2018Greater Boston Area
- Northeastern UniversityHonors Early Research Assistant2016 — 2017Greater Boston Area
- NYU Polytechnic School of EngineeringIntern2016
Skills & more
+9 more
Functional ProgrammingObject-Oriented Programming (OOP)CompilersElmGoogle Tag ManagerHerokuHiveLeadershipRacketFrom Jack's professional profile.
Frequently asked questions
- Who is Jack Mastrangelo?
- Jack Mastrangelo is a cofounder of Cobblestone who previously worked as a software engineer at Ramp and Facebook.
- Where does Jack Mastrangelo work?
- Jack Mastrangelo is Founder of Cobblestone.
- What companies did Jack Mastrangelo found?
- Jack Mastrangelo founded Cobblestone.
- Where did Jack Mastrangelo go to school?
- Jack Mastrangelo studied at Northeastern University (Bachelor of Science (B.S.), Mathematics and Computer Science).
Founder mafias
Y Combinator mafia10,230
Also came through, then founded or led a company.
+ 10,223 more
Ramp mafia25
Also came through, then founded or led a company.
+ 18 more
Ramp mafia25
Also came through, then founded or led a company.
+ 18 more
Gatherly mafia3
Also came through, then founded or led a company.
Crosby mafia2
Also came through, then founded or led a company.
Same school
Also attended Northeastern University477
+ 471 more
Shared employers
Also worked at Moab1
Also worked at 1001
Also worked at Crosby7
+ 1 more