Alex (In Seon) Yoo

About Me

Who is behind the systems?

YooCode was built on a simple idea: businesses deserve software that works their way.

I’m Alex Yoo, and I specialize in building tailored systems that streamline workflows, eliminate inefficiencies, and scale alongside growing companies.

Every solution I develop is designed with clarity, performance, and long-term growth in mind—because great software isn’t just built to function, it’s built to last.

Java

Spring Boot

Python Automation

Distributed Systems

Production Reliability

Cloud Platform

AI Integration

Experience

Software Engineer

JB Mobility

May 2023 - January 2026 | California, United States

Developed and maintained backend APIs for reliable integrations and performance.
Built Python automation to compare legacy and modern API responses for data integrity.
Diagnosed and resolved production API issues to improve reliability and user experience.

Backend Developer

UCompanion

October 2020 - April 2022 | Gangnam District, Seoul, South Korea

Led backend service development using Spring Boot, JPA, and MyBatis.
Delivered systems for enterprise clients including Hyundai Capital and Samsung Fire and Marine Insurance.
Collaborated with cross-functional teams to ship stable backend capabilities.

Web Developer

Wiin

November 2022 - March 2023 | Gangnam District, Seoul, South Korea

Developed healthcare and e-commerce services with Java and Spring MVC.
Integrated secure payment features for seamless transactions.
Partnered with teams through SVN and Slack to streamline delivery.

GIS Research and Development Staff

CMWorld

July 2019 - July 2020 | Guro-gu, Seoul, South Korea

Expanded GIS frontend capabilities using Java, JavaScript, CSS, HTML, SQL, and Spring.
Contributed to an online braille map project for visually impaired users.
Supported development of WorldStudio, a GIS engine for mapping workflows.

Projects

API Migration Validation Automation

Python
SQL
REST API
Automation
CI/CD
PostgreSQL
Jenkins

Built Python-based validation automation to compare legacy and modern API responses across databases, improving migration confidence and release safety.

Automated cross-environment API response comparisons
Protected data integrity during system transitions
Shortened QA feedback loops for backend releases

Healthcare and E-commerce Platform Engineering

Java
Spring MVC
MyBatis
Payments
Microservices
Oracle DB
Redis
Swagger
Jenkins

Led backend feature delivery for healthcare and commerce services, integrating secure payment workflows and stabilizing API behavior across releases.

Implemented payment-related backend flows with Spring MVC and MyBatis
Improved API reliability through systematic debugging
Collaborated across product, QA, and engineering for delivery

GIS Accessibility and Mapping Systems

GIS
Java
JavaScript
Mapping
Accessibility
REST API
PostGIS
three.js

Contributed to GIS R&D initiatives including an online braille map project and core GIS engine development focused on practical accessibility and mapping performance.

Supported GIS frontend and platform functionality
Contributed to an accessibility-focused braille map initiative
Delivered mapping features for production GIS workflows

Built for Businesses Ready to Scale

YooCode is designed for organizations that need software to work the way their business actually operates.

If you're:

Spending hours on repetitive tasks that could be automated
Managing disconnected tools that don't integrate well
Outgrowing off-the-shelf platforms
Exploring AI, custom applications, or internal systems
Lacking the internal engineering resources to build scalable solutions

Then custom software isn't a luxury, it's the next step.

Whether you're in Santa Rosa or operating nationally, YooCode builds systems that streamline operations, reduce friction, and support long-term growth.

Get in Touch

Have a project in mind? I’d love to hear about it. Reach out, and let’s build something that works your way. I typically respond within 24–48 hours.

Santa Rosa, California, United States

LinkedIn GitHub