// full-stack engineer · since 2002

LEONARDO VASCONCELLOS

From Doctors Without Borders to smart cities — two decades building the software people depend on.

I take tangled, mission-critical systems and make them scale: clean, fast, built to last.

// about · how to work with me

Hi, I'm Leonardo

Turning tangled, mission-critical systems into software people depend on.

I am a seasoned full-stack engineer with more than 15 years of experience building software solutions for the web – some 70 projects spread out over five distinct generations of the technology. I have served as a technical lead on an Ebola relief records management system for Doctors Without Borders, scaled a high-concurrency SaaS product at Email on Acid, and assisted in making Itajaí Brazil's top-rated smart city. My area of expertise lies in building mission-critical solutions with inherent risks involved; I tackle those (often complicated) systems and bring them from unreliable to scalable, neat, fast and robust. I am still active on the ground every day, now with the help of AI and speak English and Portuguese. In my spare time, I play bass, drums and guitar – the discipline and timing remains the same, the instrument changes.

// what I do

Full-stack engineering

Front to back, web and Android — React/Next, .NET, Java. The full path from database to pixel.

Mission-critical systems

Records, supply chains, public services — systems where downtime costs more than money.

Untangling legacy

Taking software that has grown tangled over years and making it scale again — without a rewrite.

// education & certifications

2017

Bachelor's Degree in Computer Science

Finished at UNICESUMAR the course started at UDESC.

2019

Postgraduate in Project Management

UNICESUMAR - Universidade Centro Superior Maringá.

2022

Master's Degree in Software Engineering - Incomplete

Universidade Tecnológica Federal do Paraná — UTFPR.

2014

TOEFL - Test of English as a Foreign Language

Score: 617 of 677 - C1 Level.

2000

Microsoft Certified Professional - MCP

Microsoft - Windows NT.

// tech stack

JavaScript

TypeScript

React

Next.js

Node.js

.NET

Java

Android

PHP

PostgreSQL

SQL Server

AWS

Git

Docker

Tailwind

~20years experience

~70shipped projects

5eras of the web

1M+views, prior site

// five eras, still writing code

2002ASP / PHP

2009Flash / Flex

2012Java / Android

2016.NET

2021React / Next · AI

// selected work

Selected work

See all ~70 projects

// accessible interactive fiction · inclusion for blind readers

Histórias do Juca

Choice-based interactive fiction, engineered to actually work with screen readers — the same adventure, alive for readers who see and readers who don't.

Accessibility-first game engine, verified against real screen readers
Decoupled a content-agnostic story engine from JSON-defined story graphs
Made every scene work hands-free and shareable out of the box

Engineered with

TypeScript

HTML

CSS

Next.js

React

View details

// nonprofit website · instituto do câncer

Instituto do Câncer Sempre Com Você

The official website for a cancer care NGO in Joinville, Brazil.

Blog with real patient stories
Monthly donation flow
Animated navigation with mobile submenu

Engineered with

TypeScript

JavaScript

HTML

CSS

Python

View details

// clinic management system · easy clinic

Easy Clinic

A full-featured medical clinic management system covering patient records, appointment scheduling, prescriptions, exam tracking, and billing analytics — built for Brazilian healthcare practices.

Full-stack reactive clinic platform
Custom clinical documentation engine
Zero-infrastructure PWA edition

Engineered with

JavaScript

HTML

CSS / LESS

Meteor

MongoDB

View details

// email marketing · CRM for direct-mail campaigns

Re@cher WebMailer

A full-fledged email marketing and CRM platform with SpamAssassin-powered spam-score pre-checks, segmented targeting, and a built-in HTML campaign editor.

Spam-score pre-flight checks
Segmented campaign targeting
Closed-loop tracking and list hygiene

Engineered with

PHP

JavaScript

HTML

CSS

MySQL

View details

// the engine

Writing

My technical blog. At first the idea was to build a cheat sheet of technical things so I wouldn't forget them. It turns out the blog has already passed a million views!

Android

DualBoot With SafeStrap and CyanogenMod 11 [Android KitKat 4.4.2 on the Motorola Droid Razr XT910]

In this post we'll detail the installation and configuration of SafeStrap Recovery to create a DualBoot between the Stock ROM — which supports HDMI and FullHD (1080p) video recording — and CyanogenMod 11 with

Jan 10, 20144 min readRead

Android

Installing Debian Linux on the Galaxy Tab 10.1

Ever since I bought the Galaxy Tab I'd read that it was possible to run Linux on Android. I soon saw that this could be useful: having a complete Linux system at your fingertips. Even better: I even bought the keyboard doc

Nov 26, 20126 min readRead

Hardware

Installing Debian Squeeze on the D-Link DNS-320 NAS

This is the second part of the Debian Linux configuration guide for the D-Link DNS-320 NAS. I'm assuming you already have a working installation of fonz fun_plug on your NAS; otherwise c

Oct 21, 20122 min readRead

All writing

// in their words

Testimonials

A few words from people I've built with.

Super attentive, both over WhatsApp and during the home visits he made. I recommend him. He promptly handled the demands for my website and my company's networking strategies, and he also gave personalized support to my father (an 80-year-old man), who needed a lot of attention and patience, honoring these commitments, explaining things clearly and delivering results.

Lauro NetoOwner at Ritmo Saúde · Was Leonardo's clientinvia LinkedIn · Oct 2026

Leonardo is a great professional, always eager to get to work and face challenges. He is very skilled both on frontend and backend development, as well as development processes and architecture. He is always open for work discussions, giving awesome ideas for the job in question. As a person, he is very passionate on what he does and he gives a pleasant, light and funny conversation every time we talk. I highly recommend Leonardo's work.

Thiago LPSenior Software Engineer · Worked with Leonardo on the same teaminvia LinkedIn · Apr 2020