Haeyoung Jeong, also known as hae02y, is a backend developer focused on building reliable backend systems with Java and Spring Boot.
I work across API design, data processing, cloud infrastructure, deployment automation, and production operations using technologies such as AWS, NCP, Docker, Kubernetes, and CI/CD pipelines.
My portfolio is not limited to software development projects. I also care about AI automation, operational workflows, technical documentation, product experiments, and practical systems that solve real problems.
I value clear structure, maintainable decisions, and written context that helps teams understand not only what was built, but why it was built that way.
Experience Total experience 5 years 7 months
Meninblox
2026.03 - Present
Senior Researcher · Backend / AI Development
MENINBLOX is a medical AI startup expanding healthcare administration automation and global healthcare services through the medical-specialized LLM MediKoGPT and the hyper-personalized fitness platform Ailix.
VEStellaLab
2024.01 - 2026.03
Senior Researcher · Backend Development
A smart mobility startup providing Vision-AI-based indoor precise positioning and non-GPS parking navigation services.
Joeun Technology
2020.08 - 2023.04
Assistant Manager · Network Engineer
An IT service company that supplied control center and smart-city solutions to more than 50 local governments and public institutions across Korea.
Key Work
VEStellaLab
Watchmile Parking Navigation Backend Development
Java, Spring Boot, Spring Security, Mybatis, MySQL, Thymeleaf, NCP
2024.05 - Present
Backend Team Leadership for Watchmile
Established backend development standards and documented architecture, deployment, and operations guides during the rollout of the integrated Watchmile service, reducing onboarding time by more than 50% so non-developers and interns could support feature expansion and operations.
Led overall architecture design, domain modeling, and deployment strategy, then systematized production incidents and performance issues through RCA to reduce recurrence by more than 60%.
Designed and implemented integration with parking barrier-gate devices, building an event-driven flow that sends FCM push notifications in real time for vehicle entry and exit events and reducing control-room response time to under three seconds on average.
Introduced a RabbitMQ-based message queue architecture to handle concurrency and traffic spikes in real-time AI video-analysis data collection, separating device ingestion from business processing to improve peak-time stability.
Designed internal and external integration APIs around OpenAPI 3.0 and Swagger documentation, providing clear interface standards for contracts, external submissions, and partner integrations.
Legacy Watchmile Service Migration
Designed and applied a unified backend structure to replace site-specific fragmented operations.
Separated synchronous and asynchronous flows based on real-time status updates and traffic patterns, and split read APIs from state update logic to keep responses stable under high traffic.
Container-Based Deployment Strategy and CI/CD
Built Jenkins and integrated it with GitLab to replace manual EC2-based deployments, reducing deployment lead time from 20 to 10 minutes in development and from 25 to 11 minutes in production.
Standardized distributed services into a Docker Compose stack and designed a Traefik-based reverse proxy architecture, simplifying deployment and rollback while removing configuration drift and manual operations issues.
VEStellaLab
MLOps
Java, Spring Boot, Spring Security, Mybatis, MySQL, Thymeleaf, NCP
2025.06 - Present
Unified Parking Operator API Migration
Replaced direct DB procedure integrations across five parking operators with a unified API gateway and common domain model, improving scalability and maintainability.
Cloud Migration
Migrated an on-premise service to NCP NKS.
Parking Operations Admin and Public Service Development
Designed and applied a unified backend structure to replace site-specific fragmented operations.
Separated synchronous and asynchronous flows based on real-time status updates and traffic patterns, and split read APIs from state update logic to keep responses stable under high traffic.
VEStellaLab
iCoding Talkbot Digital Textbook Backend Development
Java, Spring Boot, Spring Security, Mybatis, MySQL, Thymeleaf, NCP
2024.09 - 2025.01
Designed and implemented JWT-based authentication and authorization, user session state management, and shared utility modules.
Developed WebSocket-based real-time quiz flow and participant broadcast logic.
Modularized common account-management REST APIs and R2DBC-based asynchronous database integration, optimizing transaction handling.
Built an automated deployment pipeline for NCP Kubernetes using Nexus3 and Bitbucket Pipelines.
Designed and applied independent Spring Boot application modules for each service with an MSA-oriented architecture.
VEStellaLab
ParkOps Parking Monitoring Dashboard Development
Java, Spring Boot, Spring Security, Mybatis, MySQL, Thymeleaf, NCP
2024.01 - 2024.06
Analyzed GS certification requirements from a frontend perspective and redesigned UI structure and rendering to satisfy accessibility, security, and functional suitability requirements.
Designed and built an i18n architecture supporting Korean, English, Japanese, Chinese, and German, standardizing translation resources and keys while reducing initial loading resources by about 30% with lazy loading.
Implemented a statistics dashboard combining ApexCharts visualizations with a DataGrid to show occupancy, turnover, and dwell-time metrics, reducing decision-making time for operators by about 40%.
Built an FFmpeg-based CCTV streaming server that converts RTSP streams to HLS, enabling stable real-time video delivery for multiple clients and stabilizing latency and reconnection issues within operational limits.
Productivity & Automation
VEStellaLab
Drawing Data Change Automation Process
Java, Spring Boot, Spring Security, Mybatis, MySQL, Thymeleaf, NCP
2025.10 - Present
Figma Plugin-Based Error Validation Automation
Designed and deployed a Figma plugin that validates errors while converting designer-created drawings into data, reducing human error from an average of 20% to 0%.
Drawing and Navigation Data Validation Dashboard
Designed and implemented an internal validation dashboard that visualizes drawing and navigation data registration status for non-developers as the first checkpoint.
Reduced the process from error detection to normalization from more than five days to five minutes.
VEStellaLab
TIG Stack Monitoring Process
Java, Spring Boot, Spring Security, Mybatis, MySQL, Thymeleaf, NCP
2025.10 - Present
Built a monitoring system with Telegraf, InfluxDB, and Grafana.
Designed and operate an internal Infra Operation System for tracking site-level incidents.
Education
Hanyang University Graduate School of AI Convergence2026.03 - 2028.02
M.S. candidate in AI Convergence
Korea National Open University2021.03 - 2023.08
B.S. in Computer Science
Daedeok University2019.03 - 2021.02
Associate degree in Computer Engineering
Activities
Codestates Software Developer Bootcamp
Bootcamp
Bootcamp Completion
Studied object-oriented programming with Java and Spring and wrote learning retrospectives.
Practiced algorithm problem solving, assignments, pair programming, and code reviews.
Open Source Contributions
Open Source
Google A2A
Contributed a bug fix to Google A2A(a2a-java) for listTasks status wire string handling: PR #578.
Study Activities
Study
Study Participation
Participated in the VEStellaLab developer study, sharing engineering insights and weekly blogging feedback with internal developers.
Ran a Java algorithm study, solving Baekjoon and Programmers problems in Java and providing feedback.
Participated in a Computer Science study to strengthen CS fundamentals and engineering knowledge.
Blogging and Writing
Blog
Blog Operations
Built a technical blog with Next.js and Markdown to document technical work and lessons learned.