Hello, world! I am

João Costa

Software Engineer

I craft clean, high-performance software and lead small engineering projects, combining strong technical roots with hands-on delivery.

Let's Build Something View My Work

01. About Me

I am a software engineer focused on building clear, reliable software. I enjoy architecting backend systems and writing responsive, fast applications.

Across my projects, I've built everything from full-stack web apps to desktop tools and a lot of game mechanics. I place high value on technical clean code and direct, honest communication.

Whether writing C++ for low-level systems or building a full-stack web application, my approach is straightforward: solve real problems with practical, maintainable code.

02. What I Build

Web Development

Building fast, intuitive web applications with modern frameworks. I focus on clean interfaces, responsive UX, and eliminating unnecessary frontend bloat.

Software Development

Architecting backends, desktop tools, and custom business software. I care about solid data structures, reliable APIs, and systems that just are simple and work.

Game Development

Developing gameplay systems, mechanics, and interactive prototypes. I focus on real-time logic, performance tuning, and clean modular code.

03. Technologies & Skills

// Core Stack Showcase

C++

Java

JavaScript

Lua

PHP

Python

Rust

Svelte

Swift

TypeScript

Bash Script

Batch Script

.NET

Angular

AnimeJS

Capacitor

Django

Electron

Expo

Express

Framer Motion

GSAP

NestJS

Next.js

Nuxt.js

React

Tauri

Vue.js

Bootstrap

CSS3

HTML5

React Bits

React-Spring

Sass

shadcn/ui

Tailwind CSS

Appwrite

DBeaver

Firebase

MongoDB

MySQL

MySQL Workbench

Neon Serveless

PostgreSQL

Prisma

Redis

SQLite

Stack Auth

Supabase

Apache

Docker

Node.js

npm

pnpm

Vercel

yarn

CMake

EditorConfig

ESLint

Gradle

Git

GitHub

GitLab

packwiz

Prettier

Replit

Turbo Repo

Vite

Vitest

Webpack

JetBrains

Mendix

VS Code

VS Codium

Visual Studio

Replit IDE

Zed

Antigravity IDE

Cursor

Devin

Kiro

Godot

Unity

Unreal Engine

Roblox Studio

Linux

macOS

Windows

C++

Java

JavaScript

Lua

PHP

Python

Rust

Svelte

Swift

TypeScript

Bash Script

Batch Script

.NET

Angular

AnimeJS

Capacitor

Django

Electron

Expo

Express

Framer Motion

GSAP

NestJS

Next.js

Nuxt.js

React

Tauri

Vue.js

Bootstrap

CSS3

HTML5

React Bits

React-Spring

Sass

shadcn/ui

Tailwind CSS

Appwrite

DBeaver

Firebase

MongoDB

MySQL

MySQL Workbench

Neon Serveless

PostgreSQL

Prisma

Redis

SQLite

Stack Auth

Supabase

Apache

Docker

Node.js

npm

pnpm

Vercel

yarn

CMake

EditorConfig

ESLint

Gradle

Git

GitHub

GitLab

packwiz

Prettier

Replit

Turbo Repo

Vite

Vitest

Webpack

JetBrains

Mendix

VS Code

VS Codium

Visual Studio

Replit IDE

Zed

Antigravity IDE

Cursor

Devin

Kiro

Godot

Unity

Unreal Engine

Roblox Studio

Linux

macOS

Windows

C++

Java

JavaScript

Lua

PHP

Python

Rust

Svelte

Swift

TypeScript

Bash Script

Batch Script

.NET

Angular

AnimeJS

Capacitor

Django

Electron

Expo

Express

Framer Motion

GSAP

NestJS

Next.js

Nuxt.js

React

Tauri

Vue.js

Bootstrap

CSS3

HTML5

React Bits

React-Spring

Sass

shadcn/ui

Tailwind CSS

Appwrite

DBeaver

Firebase

MongoDB

MySQL

MySQL Workbench

Neon Serveless

PostgreSQL

Prisma

Redis

SQLite

Stack Auth

Supabase

Apache

Docker

Node.js

npm

pnpm

Vercel

yarn

CMake

EditorConfig

ESLint

Gradle

Git

GitHub

GitLab

packwiz

Prettier

Replit

Turbo Repo

Vite

Vitest

Webpack

JetBrains

Mendix

VS Code

VS Codium

Visual Studio

Replit IDE

Zed

Antigravity IDE

Cursor

Devin

Kiro

Godot

Unity

Unreal Engine

Roblox Studio

Linux

macOS

Windows

C++

Java

JavaScript

Lua

PHP

Python

Rust

Svelte

Swift

TypeScript

Bash Script

Batch Script

.NET

Angular

AnimeJS

Capacitor

Django

Electron

Expo

Express

Framer Motion

GSAP

NestJS

Next.js

Nuxt.js

React

Tauri

Vue.js

Bootstrap

CSS3

HTML5

React Bits

React-Spring

Sass

shadcn/ui

Tailwind CSS

Appwrite

DBeaver

Firebase

MongoDB

MySQL

MySQL Workbench

Neon Serveless

PostgreSQL

Prisma

Redis

SQLite

Stack Auth

Supabase

Apache

Docker

Node.js

npm

pnpm

Vercel

yarn

CMake

EditorConfig

ESLint

Gradle

Git

GitHub

GitLab

packwiz

Prettier

Replit

Turbo Repo

Vite

Vitest

Webpack

JetBrains

Mendix

VS Code

VS Codium

Visual Studio

Replit IDE

Zed

Antigravity IDE

Cursor

Devin

Kiro

Godot

Unity

Unreal Engine

Roblox Studio

Linux

macOS

Windows

Programming Languages

C++

Java

JavaScript

Lua

PHP

Python

Rust

Svelte

Swift

TypeScript

Automation & Scripting

Bash Script

Batch Script

Frameworks & Libraries

.NET

Angular

AnimeJS

Capacitor

Django

Electron

Expo

Express

Framer Motion

GSAP

NestJS

Next.js

Nuxt.js

React

Tauri

Vue.js

Design & Styling

Bootstrap

CSS3

HTML5

React Bits

React-Spring

Sass

shadcn/ui

Tailwind CSS

Databases & Backend

Appwrite

DBeaver

Firebase

MongoDB

MySQL

MySQL Workbench

Neon Serveless

PostgreSQL

Prisma

Redis

SQLite

Stack Auth

Supabase

Runtimes & Environments

Apache

Docker

Node.js

npm

pnpm

Vercel

yarn

Dev Tools

CMake

EditorConfig

ESLint

Gradle

Git

GitHub

GitLab

packwiz

Prettier

Replit

Turbo Repo

Vite

Vitest

Webpack

IDEs

JetBrains

Mendix

VS Code

VS Codium

Visual Studio

Replit IDE

Zed

Agentic Dev Environments

Antigravity IDE

Cursor

Devin

Kiro

Game Dev

Godot

Unity

Unreal Engine

Roblox Studio

Operating Systems

Linux

macOS

Windows

04. Featured Projects

TaskTitan

Confidential

A project management desktop application with local-first design, built using Electron, Next.js, NestJS, PostgreSQL, and TypeScript in a Turborepo monorepo.

Next.jsElectronTailwind CSSCSS3PrismaNestJSPostgreSQLDockerNode.jsExpress.jsTypeScriptTurborepo

Antonio Costa Workshop

Confidential

A custom web application designed for Antonio Costa Company to streamline workshop operations, client interactions, and internal management. Features AI capabilities to assist with daily workflows.

AngularRustTypescriptHTMLCSSTauriDocker

AI Toolkit

Open Source

A systemic prompt engineering and evaluation framework. Features advanced meta-cognitive agent personas, few-shot dynamic context injection, schema-validated test assertions, and an interactive CLI playground powered by LiteLLM.

PythonLiteLLM

Source Code

Code Pulse v2

Open Source

Code Pulse is an extension to keep track of your productivity and coding patterns to help you out. It provides smart insights, trends, complexity, and more to improve your coding standards and quality.

TypeScriptVSCode

Source Code

Portfolio Website v3

Open Source

A modern, fully server-side rendered portfolio built with Nuxt 4 and Vue 3. Features scroll-based animations, i18n (EN/PT), WCAG 2.1 AA compliance, Nuxt UI, Tailwind CSS v4, and a fully data-driven content architecture.

NuxtVue 3Tailwind CSSTypeScriptVercelCSS3

Live Demo Source Code

DailyDash

Open Source

DailyDash is a JavaFX desktop app that makes task management faster, safer, and easier. It is designed for a smooth cross-platform experience on Linux, macOS, and Windows.

JavaFXJavaGradleMaven

Source Code

FreeChatium

Open Source

FreeChatium is a serverless edge AI workspace powered by Puter.js and OpenRouter, with support for 100+ models, multimodal vision, sandboxed code execution, cloud storage, and PWA delivery.

TypeScriptReactNext.jsPuter.jsOpenRouter APIVercelTailwind CSSassistant-uishadcn/ui

Source Code

Evara-UI

Open Source

Evara-UI is an open-source, highly scalable UI library and design system with modular, consistent, and testable components, plus built-in support for performance, SEO, analytics, and backend-driven workflows.

TypeScriptpnpmTurborepo

Source Code

BeaudyShell

Open Source

BeaudyShell is a modern, extensible, and highly accessible Rust-based shell with a polished REPL experience, real-time syntax highlighting, inline autocompletion, tab-cycled suggestions, and command history restoration.

RustCLIREPLShellTerminal UI

Source Code

The Great Calculator v4

Open Source

The Great Calculator is a high-precision calculator with scientific mode, graphing mode, functions, and probability tools, designed to feel fast, clear, and accurate.

Next.jsReactTailwindCSSTypescriptMath.jsVercel

Live Demo Source Code

05. Professional Experience

Founder & Lead Developer

23/08/2023 - 01/01/2026

Selkira Inc

Founded and led systems development for indie game projects, managing core technical architecture and team workflows. Designed gameplay mechanics and state management using C++ and modern tooling. Established Git version control standards, CI workflows, and technical documentation to keep multi-member development organized.

Web Developer

10/05/2023 - 29/07/2023

Antonio Costa

Developed custom web software for a workshop client, streamlining daily operations and client tracking. Conducted discovery sessions to map business requirements into clear technical specs, optimized performance bottlenecks for fast loading, and delivered a responsive, easy-to-maintain application on time.

06. Hobbies & Interests

Gaming

Exploring virtual worlds and analyzing game mechanics, which fuels my passion for game development.

Moto Riding

Seeking adrenaline on the open road and exploring new places on two wheels.

Coding

Writing code as a hobby and constantly learning new technologies.

07. What's Next?

Let's Build Something Together

My inbox is always open. Whether you have a question, a project proposal, or just want to say hi, I'll try my best to get back to you!

Say Hello GitHub