Creator of Lextrix

Reetesh Kumar

Creator of Lextrix · Software Engineer · Open Source Builder · Generative AI Engineer

Reetesh Kumar builds developer tools, open-source software, and AI-powered applications. Lextrix — an open-source modular typescript rich-text editor with changeset ot and html, markdown, and mdx serialization. — is the flagship project.

GitHub LinkedIn npm

developer = {
    "name": "Reetesh Kumar",
    "role": "Creator of Lextrix · Software Engineer · Open Source Builder",
    "focus": [
        "Lextrix Ecosystem",
        "Backend Engineering",
        "Developer Tools",
        "Generative AI"
    ],
    "currently": [
        "Lextrix",
        "Sudoku Engine"
    ]
}

print(developer)

About

Reetesh Kumar is a software engineer and open-source builder. Lextrix — an open-source modular typescript rich-text editor with changeset ot and html, markdown, and mdx serialization. — is his flagship project.

The work centers on TypeScript, React, Next.js, and generative AI — with an emphasis on clear architecture, measurable performance, and software other engineers can extend.

Follow open-source work on GitHub, connect on LinkedIn, or read the About page for the full story behind Lextrix.

Lextrix Ecosystem

An open-source modular TypeScript rich-text editor with ChangeSet OT and HTML, Markdown, and MDX serialization.

Lextrix

Modern rich-text editing for the web

An open-source modular TypeScript rich-text editor with ChangeSet OT and HTML, Markdown, and MDX serialization. Compose packages for document models, formatting, change processing, serialization, and UI — or ship the full bundle. Built for engineers who want predictable editor behavior, native Markdown/MDX import-export, and open-source ownership.

Snow themeBubble themeSlate themeDawn theme

Modular by design

Use the published lextrix bundle or compose lextrix-core, lextrix-dom, lextrix-formats, lextrix-modules, lextrix-serialize, and lextrix-ui for custom builds.

Native serialization

importContent / exportContent for HTML, Markdown, MDX, and JSON — all routed through ChangeSet via lextrix-serialize.

Predictable change pipeline

ChangeSets with compose, diff, transform, and invert — a solid foundation for undo/redo and future collaboration features.

Framework agnostic

Works with React, Vue, Angular, Svelte, or vanilla JavaScript — the engine owns document state, not your UI framework.

Extensible registry

Selected Work

Projects, libraries and tools I have built or am actively working on.

Featured

Lextrix

Open Source

An open-source modular TypeScript rich-text editor with ChangeSet OT and HTML, Markdown, and MDX serialization.

TypeScript • Editor Engine • npm

Featured

Sudoku Engine

Libraries

TypeScript puzzle generator, solver, and game helpers — classic 9×9 plus 6×6, Sudoku X, and Hyper variants.

TypeScript • Algorithms • npm

Featured

2048

Side Projects

Sliding tile puzzle with smooth animations and a responsive layout.

React • Game Dev • Canvas

Side Projects

Browser experiments — puzzles and board games built to sharpen engine design and UX craft. Lextrix remains the flagship.

Sudoku

Puzzle

Advanced sudoku solver and game with AI-powered hints

Tiger and Goat

Strategy

Traditional tiger and goats strategy game with modern UX

Tic Tac Toe

Strategy

3×3 classic with expert AI, difficulty tiers, local two-player, and optional timed moves

Open Source Work

Libraries and ecosystems published by Reetesh Kumar on GitHub and npm.

Lextrix

An open-source modular TypeScript rich-text editor with ChangeSet OT and HTML, Markdown, and MDX serialization.

Sudoku Engine

TypeScript puzzle generator, solver, and game helpers — classic 9×9 plus 6×6, Sudoku X, and Hyper variants.

GitHub Profile

Open-source repositories by Reetesh Kumar

Technical Expertise

Engineering focus areas for teams, recruiters, and collaborators evaluating Reetesh Kumar.

Lextrix Ecosystem

Modular rich-text editing — document models, ChangeSets, themes, and lextrix-ui for production editors.

TypeScript & React

Typed frontends, component architecture, and Next.js App Router production patterns.

Developer Tools

Editor engines, npm libraries, and APIs designed for other engineers to extend.

Generative AI

Practical AI integration in tooling and workflows — applied engineering, not hype.

Open Source

Long-horizon OSS published on GitHub and npm, led by the Lextrix editor ecosystem.

Frontend Architecture

Document models, state boundaries, performance, and maintainable module design.

Blog & Articles

Engineering notes on TypeScript, React, editor architecture, games, and shipping software.

EngineeringMay 30, 2026

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.

EngineeringMay 28, 2026

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.

EngineeringApr 28, 2026

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.

Writing

Articles on TypeScript, editor architecture, and shipping real software — including deep dives that informed Lextrix.

Technical writing about rich-text editors, React patterns, and open-source tooling. Conference talks — when scheduled — will appear here.

Tech Stack

View full stack →

Python

Flask

FastAPI

React

Node.js

Docker

Connect with Reetesh Kumar

Open to conversations about Lextrix, open-source tooling, TypeScript, and software engineering.

GitHub — rishureetesh LinkedIn — Reetesh Kumar

About Reetesh Kumar →

Reetesh Kumar

Creator of Lextrix · Software Engineer · Open Source Builder · Generative AI Engineer

developer = { "name": "Reetesh Kumar", "role": "Creator of Lextrix · Software Engineer · Open Source Builder", "focus": [ "Lextrix Ecosystem", "Backend Engineering", "Developer Tools", "Generative AI" ], "currently": [ "Lextrix", "Sudoku Engine" ] } print(developer)

Lextrix

Modern rich-text editing for the web

Snow themeBubble themeSlate themeDawn theme

Reetesh Kumar

About

About Reetesh Kumar

Lextrix Ecosystem