PORTFOLIO · 2026

I build AI tools
and verify the results

Since joining Samsung Electronics MX in 2014, I have worked on apps, cloud backends, and frontends. I now build an internal LLM agent that supports development. Outside work, I build and use tools that reduce repetitive tasks at my spouse’s administrative services office. These projects document what I have learned from building and operating them myself.

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Developing at Samsung: 12+ years
Personal projects documented: 14
Reviewing one notice (previously 1–2 hours): ~20 min

Profile cardJaehoon Jeong12+ yearsExperience

LLM AgentReactSpring Boot

JAEHOON JEONG · SAMSUNG ELECTRONICS MXA developer building LLM agents

Samsung Electronics MXSenior developer · Joined in 2014

Personal projectsBuilding and operating tools with Claude Code and Codex

JavaScriptTypeScriptReactVueJavaSpring BootPythonMongoDBAzureClaudeCodexLLM Agent

github.com/himangga01

FEATURED

Featured

Procurement Notice Reviewer

Problem: Reading notices and attached PDFs, then checking them against clients’ supporting documents, took 1–2 hours per notice.
Approach: I collected notices through public-data APIs, read scanned documents with PaddleOCR, retrieved references with RAG, and used Gemini to organize the requirements. I defined merge rules so an AI ‘Satisfied’ assessment becomes ‘Needs review’ without documentary evidence, and rule-based decisions take precedence when confidence is low.
Result: In practical use, review time fell to about 20 minutes per notice. I added 216 tests for the decision logic.
My role: Requirements and decision-rule design
Defining test criteria
Incorporating practical feedback

PythonGeminiRAG

GitHub

Two Office Websites

Problem: The office needed an online presence and a reliable way to receive consultation requests.
Approach: I built both sites using Node built-in modules without external packages and published them from one Mac mini through Cloudflare Tunnel. Consultation requests trigger email and Telegram notifications. Visitor statistics are anonymous and use no cookies.
Result: The office website has 56 pages in four languages. The school violence guidance site launched in August 2026. I diagnosed and fixed an external-access failure after a reboot and left a script to recover from the same issue.
My role: Architecture and privacy decisions
Server and domain operations
Incident response

JavaScriptNodeClaudeCloudflare

Website Website Private repository

Korean Text Polisher

Problem: AI-written Korean often retained translated phrasing and mechanical lists, making it difficult to use as-is.
Approach: I built a Windows app and skills that use Claude Code or Codex for polishing. A verification step restores the original sentence whenever numbers, quotations, or proper nouns change.
Result: Short-document processing dropped from 262 to 106 seconds. It missed the target of at most 40% of the original time by 0.5 percentage points, so I did not make it the default. I also used this tool to review the wording in this portfolio.
My role: Polishing rules and verification design
Performance measurement criteria
Distribution packaging

PythonTypeScriptClaude

Private repository

CAREER · EDUCATION

Experience & Education

Since joining in 2014, I have moved through apps, cloud backends, and frontends. Today I develop LLM agents.

Company: Samsung Electronics MX
Period: Mar 2014 – Present
Position: CL3 (Senior)

2025 – PresentCurrent work

Internal Development-Support LLM Agent
I design and implement an internal LLM agent that interprets requirements and UX-team Figma deliverables to generate and verify frontend code. I lead the work from requirements, architecture and prompt design to test automation, deployment, and operations.
LLM AgentPrompt designFigma interpretationTest automation
2020 – PresentCurrent work

Android OS Update & Financial Asset Protection Frontends
I develop frontends for Samsung device Android OS updates and a remotely managed financial asset protection service. Using React, JavaScript, and TypeScript, I build screens and core features, handle operations and incidents, and improve performance and quality. I coordinate development issues with labs in the Philippines, Canada, and the United States.
ReactJavaScriptTypeScriptGlobal collaboration
'19 ~ '20

C-Lab AIOS MIXY
I planned and implemented an IoT cooking solution, participating from the proposal and team-formation stages. I designed and developed AI-based personalized recipe recommendations using user data, designed APIs and databases, built and operated Azure infrastructure, and turned motion-recognition data into recipe steps.
AI recommendationsAzureIoTAPI & database design
'16 ~ '19

Knox Configure Backend
I developed Knox Configure cloud backend APIs, migrated MySQL to MongoDB, and built two new administration servers.
Cloud APIsMySQLMongoDB
'15 ~ '16

Samsung School
I developed apps for Samsung School, an educational tablet solution.
Tablet appsEducation
'14 ~ '15

HR Task Force
For one year, I planned and ran Galaxy training for employees and a two-day, one-night hackathon.
Training designHackathon operations

HOW I WORK

How I Work with AI

I built my personal projects with Claude Code and Codex as coding agents. I spent more time checking whether the results were trustworthy than simply getting code quickly.

1
Agree on the design first
I used GitHub Spec Kit to document requirements, designs, and task lists before handing off implementation.
2
Tests first
For each feature, I asked for a failing test first and recorded passing results in the work log.
3
Independent AI review
I assigned another agent to independently review the first agent’s work, incorporated the findings, and performed the final check myself.

What I handle

Requirements and priorities
Decision rules and verification criteria
Deciding which review findings to accept
Deployment, operations, and incident response

What I delegate to AI

Draft code and tests
Initial code reviews
Draft documentation

Unsupported judgments go to a person

Procurement: missing evidence means ‘Needs review’
Text polishing: changed facts revert to the original
Auction analysis: conflicting assessments require expert review

CARD PACKS

Explore the Card Packs

I grouped the projects into six card packs. Choose a category and swipe the top of its wrapper sideways to reveal the cards one by one. To browse without the animation, use the All projects list.

What the Tiers Mean Tiers reflect outcomes, not technical difficulty.

IMPACTProven impactUsed in real work with observed before-and-after results1 project
LIVELivePublicly running or available as a distributable app3 projects
TESTEDTestedCore behavior checked through test records7 projects
PLANDesignedRequirements and design documented; implementation preparation3 projects

ALL PROJECTS

All projects

All 14 projects are listed here. Click a card to see the details.

14shown

CHARACTERS

Project Characters

I drew characters that reflect each project’s purpose and technologies. The same characters appear on the project cards.

Procurement Notice ReviewerAn owl with magnifying glasses reading notices carefullyPythonGeminiRAG
Korean Text PolisherA cat correcting awkward sentences with its fountain-pen tailTypeScriptPythonClaude
Jihye Administrative Services WebsiteA globe-shaped whale with speech bubbles in four languagesNodeJavaScriptClaude
School Violence Guidance WebsiteA bear protecting students with a star shieldNodeJavaScriptCloudflare
Housing Article AutomationA penguin wearing a NEWS cap and holding a newspaperPythonDjangoCelery
Short-Form Video StudioAn octopus joining scenes with film-strip legsReactFFmpegGemini
Figma-to-Code PipelineA chameleon carrying three design layers on its backTypeScriptMCPPlaywright
Local UI Design EditorA crab cropping screens with crop-mark clawsReactExpressMCP
Court Auction Rights AnalysisA turtle comparing two judgments with scales on its shellPythonFastAPIReact
Apartment Listing TrackerA squirrel holding an apartment and tracking daily changesFastAPIPostgreSQLPlaywright
Media ConverterA bat wearing headphones and converting audio formatsKotlinFastAPIFFmpeg
Unattended Store MonitoringA firefly watching a store through camera-lens eyesYOLOGPTNext.js
Real Estate Policy DashboardA giraffe with bar-chart patterns on its bodyPostGISpgvectorReact
AI Shopping VideosA rabbit photographing products with a cameraRemotionFFmpegPostgreSQL

I build AI toolsand verify the results

Procurement Notice Reviewer

Two Office Websites

Korean Text Polisher

Internal Development-Support LLM Agent

Android OS Update & Financial Asset Protection Frontends

C-Lab AIOS MIXY

Knox Configure Backend

Samsung School

HR Task Force

Agree on the design first

Tests first

Independent AI review

What I handle

What I delegate to AI

Unsupported judgments go to a person

I build AI tools
and verify the results