About
About Reetesh Kumar
I work on backend systems during the day. In my own time I like reading source code, building side projects, and figuring out how things work under the hood.
Many of the projects here started because I wanted to understand how something worked — not because I had a product plan.
This site is where I keep the libraries, experiments, and writing that come out of that.
Full background
Selected Work
Libraries and side projects.
Featured
Blog & Articles
Engineering notes on TypeScript, React, editor architecture, games, and shipping software.
Latest articles
Why I Started Building Lextrix
Not a pitch — how reading Quill source, hitting extension walls, and building the wrong monolith first led to an open-source TypeScript editor ecosystem.
Lessons Learned Building a TypeScript Library
What broke when I published @reetesh/sudoku-engine and lextrix on npm — exports, semver, types, READMEs, and the gap between publish and maintenance.
What Reading Quill's Source Code Taught Me About Editors
Deltas, blots, clipboard pain, and selection state — tracing Quill internals and what carried over into Lextrix.