My name is Leonardo Maldonado. Software engineer from Brazil, based in Valencia, Spain. 7+ years building for the web — from early-stage startups to international product companies.

Creator of 33 JavaScript Concepts — 66K+ GitHub stars, translated into 40+ languages, recognized by GitHub as a top open-source project of 2018.

• Previously sole frontend engineer on Spaceship at Namecheap, working on their domain search product.
• Written 100+ technical articles on JavaScript, TypeScript, React, and Node.js for LogRocket and Progress.
• I build things across languages — JavaScript, TypeScript, Go, Rust — because shipping is how I learn.

• 33-js-concepts — 33 JavaScript concepts every developer should know. 66K+ stars and translated into 40+ languages by the community.
• Shopwyse — An ERP I built for retailers who need POS, inventory, CRM, and financial reporting under one roof. TanStack Start, Elysia, PostgreSQL.
• Polyglot — An AI writing assistant that interviews you first, then drafts content in your voice from different angles.
• Otis Finance — A stock market API for real-time prices, SEC filings, earnings, and financials.
• gone — I wanted a dead link detector that was actually fast, so I wrote one in Go. Concurrent, has a TUI, and works in CI.
• betterhook — A git hooks manager I built in Rust because existing ones don't handle worktrees or parallel agents well. DAG scheduling, blake3 caching, Tokio under the hood.
• rust-skills — 179 rules I wrote so AI coding agents stop guessing when they write Rust.

• LogRocket Blog — React, TypeScript, frontend architecture.
• Progress / Telerik Blog — React, Node.js, modern JavaScript.