Javier Villanueva

HYTOPIA is a modern games platform that powers voxel-based creator experiences. I helped implement the front ends for all their services that required interaction with ETH Mainnet, Polygon, and their custom L2 Blockchain based on Arbitrum Orbit; this included token swaps, staking, bridges, faucets, and many more. I also helped develop user interfaces for their Rust-based game using the Chromium Embedded Framework.

A React Native fitness app with AI-powered workout generation. As full-stack developer, I built the complete system using Expo, TypeScript, and Supabase. Engineered a RAG pipeline with Vercel AI SDK and Gemini models to generate personalized workouts based on user preferences and training history. Implemented real-time streaming for progressive UI updates, multi-day program generation, and exercise replacement. Developed auth flows, optimized caching with TanStack Query, and created polished animations with Reanimated.

HYTOPIA Studio is an Electron-based IDE for creating HYTOPIA voxel games, featuring an AI coding agent, a live in-game preview, and 3D editing tools.

The desktop app (React 19, Radix UI, Tailwind, Vite) ships with Monaco code editing, a Three.js model viewer (GLTF/GLB, animations, node hierarchy), and an embedded webview for game preview tied to the dev server lifecycle.

The AI back end (Express.js/Bun) runs on Claude Sonnet and GPT over a custom WebSocket protocol for streaming chat. The agent has 13+ tools split between server-side (VFS, RAG with pgvector) and client-side (IPC to Electron) execution, with context compaction, token budgeting, and an explore subagent for multi-file investigations.

A WebSocket bridge to a HYTOPIA SDK build plugin lets users place blocks in real time, insert schematics, and switch build/play modes. Multiplayer testing works through Cloudflared tunneling.

Luma's AI Pillow Software is a browser-based tool that measures shoulder dimensions from a photo or live camera feed to recommend the right pillow height.

The front end (React 19, TypeScript, and Vite) handles two input flows: live video and static image upload. Both run through MediaPipe's PoseLandmarker for real-time body landmark detection, with a calibration system that uses average eye width (2.42cm) as a physical pixel-to-cm reference.

The measurement engine takes multiple samples, applies median filtering and outlier rejection, and scores each result using a confidence model that weighs eye and shoulder landmark visibility. A pose validation layer checks shoulder positioning against dynamic viewport bounds before accepting any sample.

All processing runs entirely client-side with no back end required, so photos never leave the device.

An online multiplayer game where players can challenge each other and stake crypto in battles where the winner takes all. I was primarily responsible for implementing the Web3 integrations between the Phaser game and the wallets/smart contracts using a combination of Svelte, TypeScript, and multiple open source libraries. I also helped implement in-game features and optimize performance to support multiple concurrent players running without slowdowns or lag.

A back-end dashboard for gaming agencies and developers to interact with the MetaFab that provides a self-serve solution for games and gamified apps to integrate powerful blockchain infrastructure.

I developed the dashboard using React and the Remix framework while ensuring the application was performant and easy to use. I implemented best practices like streaming data and the React Suspense API to provide a smooth user experience, although data transfer was often very high.

A P2E NFT game built in the Ethereum blockchain.

I developed the smart contract to mint ERC721 tokens gas-efficiently and allowed staking and rewards. I used off-chain elements to avoid paying gas fees and created a marketplace where items can be bought using the project custom token.

A seasonal NFT collection that rewards Discord referrals with custom ERC1155 tokens. I was responsible for building the front-end and Web3 integration with the Polygon smart contracts. I worked on the functionality that allows for gasless transactions and meta-transactions so the dApp can scale to thousands of transactions per minute.

A unique NFT gamified minting experience built on Ethereum Mainnet where people could purchase and "absorb" other NFTs in the collection; the more NFTs they owned, the more points they would get. I was in charge of developing the front-end Next.js application following the design system in place and integrating it with the smart contract using the Viem and Wagmi React libraries.

A decentralized autonomous organization (DAO) for projects where you can apply for funding to promote unicycling initiatives. I created the smart contract to handle registration and voting for projects and the website and front-end interface to make interacting with it more user-friendly.

The smart contract is integrated with third-party systems that allow notifying users via email when projects are submitted, accepted, or rejected by monitoring events live in the blockchain.

An NFT project shop that allows holders to purchase virtual items with their custom ERC20 token. I helped develop the front end for the shop page and added the integration to transfer tokens to purchase each individual item. The back end uses an AWS DynamoDB to manage listings.

An app to allow ERC721 holders to stake their tokens and earn a custom ERC20 token to be able to spend in the marketplace. I developed the staking contract and the ERC20 token implementation, and the front end Web3 integration using Nuxt and Ethers.js. The staking contract is upgradeable using the UUPS proxy pattern, so it's easier to change in the future.