Benny Joo
Founder at Cal.com, Inc.
New Haven, Connecticut, United States
Summary
🤩
Rockstar🎓
Top SchoolBenny Joo is a founder and senior software engineer with seven years of experience building developer-facing products and scalable web systems. He’s contributed to high-profile open-source projects like MUI—adding components such as Masonry and fixing nuanced theming/pseudo-class issues—and has driven backend and DevOps improvements at Cal.com to enhance logging and embed functionality. A Yale MBA and former maintainer of Facebook’s jscodeshift, Benny combines product-minded leadership with hands-on engineering across front-end, back-end, and AI agent development. He’s founded multiple startups, including a BPM-sorted music app and THE DOT, which partners with founders from top tech and academic institutions on AI agent projects. Known for mentoring open-source contributors and leading small engineering teams, he brings a pragmatic mix of technical depth and entrepreneurial grit.
7 years of coding experience
5 years of employment as a software developer
Bachelor of Engineering - BEng Honours Computer Science, Bachelor of Engineering - BEng Honours Computer Science at The University of EdinburghInternational Baccalaureate Diploma, International Baccalaureate Diploma at Chadwick SchoolThe Perkiomen SchoolMaster of Business Administration - MBA, Master of Business Administration - MBA at Yale School of Management
Korean, English
Stackoverflow
1reputation
0reached
0answers
0questions
Github Skills (16)
css10
uid10
typescript10
logging10
javascript10
typescripts10
material-ui10
front-end-development10
ui-design10
react10
typescript-types10
back-end-development9
refactoring9
nextjs8
nodejs8
Programming languages (4)
Github contributions (5)
calcom/cal.com
Oct 2023 - Apr 2025
Scheduling infrastructure for absolutely everyone.
Role in this project:
Back-end & DevOps Engineer
Back-end & DevOps EngineerContributions:808 reviews, 713 PRs, 1914 pushes in 1 year 6 months
Contributions summary:Benny primarily focused on updating and refactoring the codebase, specifically targeting the improvement of logging practices. Their commits involved updating the `tslog` library and modifying logging levels across multiple files. They also worked on optimizing the application by introducing a new method and refactoring different aspects. Additionally, the user contributed to enhancing the embed functionality by modifying related code.
tailwindcssturborepotrpcprismascheduling
mui/material-ui
Aug 2021 - Jan 2023
Material UI: Comprehensive React component library that implements Google's Material Design. Free forever.
Role in this project:Front-end Developer
Front-end DeveloperContributions:16 releases, 561 reviews, 114 commits in 1 year 5 months
Contributions summary:Benny focused on enhancing the Material UI component library by addressing theme-related issues within variants, specifically fixing pseudo-class overrides and improving the merging of styles. They added a new Masonry component to the material-ui-lab library and addressed various issues by syncing the height of the textarea. Additionally, the user improved the demo styling for Masonry components and updated the position of the indicator when tab sizes change using ResizeObserver in the tabs component.
reactmuimaterialjavascriptmaterial-design
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