New Jersey · Senior Software Engineer

Oscar
Villalta.

I build software that makes
complicated work feel simple.

Full-stack applications. Thoughtful APIs. Integrations that connect the pieces.

Explore my work GitHub

Engineering with a creative side.Scroll to explore ↓

C# / .NETTypeScriptReact / RemixAWSPostgreSQL

01 / Selected work

Built around real problems.

Inventory, research, and everyday routines.
Different domains. The same care for the details.

MASTADON / COMMERCE SYSTEMS

Screenshot coming soon · Inventory & fulfillment

01 — Marketplace engineering

Mastadon

Resale inventory & marketplace platform

A full-stack platform that connects products and physical inventory to offers, marketplace listings, orders, and fulfillment.

End-to-end eBay workflows: publish, revise, end listings, ingest orders, and notify shipments.
Explicit domain boundaries and shared-stock correctness across storefronts.

.NET 10 · EF Core · PostgreSQL · Next.js · Docker · xUnit · Playwright

Personal project · Private repository

STOCK LAB / MARKET RESEARCHScreenshot coming soon · Market research

02 — Data & experimentation

Stock Lab

Market research and learning tools for anomaly detection, thesis tracking, and paper trading.

Combines market, SEC, fundamentals, macroeconomic, earnings, news, and short-interest data with reproducible ML experiments, leakage controls, and prospective validation.

React · TypeScript · Python · FastAPI · PostgreSQL · ML evaluation

Personal project · Private repository

WORKOUT LOGGER / NATIVE MOBILE

01 SHOW UP02 PUT IN THE WORK03 BUILD ON IT

Screenshot coming soon · iOS & Android

03 — Cross-platform applications

Workout Logger Universal

A fitness application with shared Kotlin domain and application logic, and independently built native interfaces.

SwiftUI on iOS and Jetpack Compose on Android, with compatibility-focused validation across the shared application layer.

Kotlin Multiplatform · SwiftUI · Jetpack Compose

Personal project · Private repository

Earlier work Where the journey started

Knockout Fitness

A website for a Muay Thai gym in Brick, New Jersey.

View source ↗

Trivia Game

A React and TypeScript trivia game using the Open Trivia DB API.

View source ↗

Chef’s Den

An early recipe-search application exploring full-stack web development.

View source ↗

Hangman

A musician-themed browser game built with HTML, CSS, and JavaScript.

View source ↗

02 / A little background

Business problems.
A builder’s mindset.

I started coding to make my own business run better. That instinct still shapes how I build software.

Before working in software full time, I co-founded an online retail business and built its product-management, inventory, and eBay-listing tools. The business grew to around 10 employees and more than $400K in annual gross sales.

Today, I’m a Senior Software Engineer at KBRA, building production web experiences, REST APIs, and event-driven integrations. My work spans C#/.NET, PHP, TypeScript, React, Remix, and AWS.

Professional experience

KBRA

Nov 2018 — Present

Senior Software Engineer

Promoted Feb 2026 · Previously Software Engineer

Financial rating interfaces, Contentful-driven publication feeds, and .NET / PHP APIs. Built event-driven marketing integrations using AWS Lambda, SQS, and SNS, and improved frontend delivery with lazy loading and code splitting.

PeachCo / NJ Pacific

2002 — Sep 2017

Co-Founder / Software Developer

Built custom retail software with PHP, JavaScript, MySQL, and eBay APIs, including barcode-assisted workflows, image handling, and listing automation, while managing day-to-day business operations.