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Software builder creating polished products across web, AI, developer tools, browser extensions, desktop apps, and systems programming.

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I build practical software products that turn ideas into usable, deployable systems.

My work spans frontend applications, AI-powered products, developer tools, browser extensions, desktop software, and low-level systems. I care about clean UX, reliable architecture, fast iteration, and shipping projects that feel complete enough to be used in the real world.

Recently, I have been working with Next.js, TypeScript, OpenAI API, Claude, JavaFX, Chrome Extension, Prisma, PostgreSQL, C, and Java.

Korean-first AI SaaS platform that turns KakaoTalk and AI conversation logs into academic-style research papers.

Highlights

• KakaoTalk .zip / .txt upload and conversation parsing
• AI-powered conversation analysis and academic paper generation
• Research dashboard for generated paper insights
• Journal-style academic paper reader
• Guest-first workflow without login friction
• Korean / Japanese / English UI support
• Dark mode ready responsive SaaS interface
• Privacy-conscious flow with raw uploads not permanently stored

Tech
Next.js, TypeScript, Tailwind CSS, Prisma, PostgreSQL, OpenAI API, Vercel

Documentation

• Technical Whitepaper (EN)
• Technical Whitepaper (KO)

Links

• Demo: https://chat-paper-platform-iota.vercel.app/
• GitHub: https://github.com/hyeonjo00/chat-paper-platform

AI-powered stock and crypto chart screenshot analysis SaaS.

Chart Insight Assistant is a Next.js application that lets users upload market chart screenshots, run cautious OpenAI-powered scenario analysis, and review structured trading insights in a clean dark UI.

Highlights

• Drag-and-drop chart screenshot upload
• Image preview with PNG, JPG, JPEG, and WEBP validation
• Server-side OpenAI chart analysis API route
• Structured analysis output: bias, confidence, entry zone, invalidation zone, take-profit targets, and summary
• Cautious scenario-based market interpretation without guaranteed predictions
• Local analysis history saved with localStorage
• Clean dark-themed responsive UI
• Google AdSense-ready monetization structure
• ads.txt verification support
• English / Korean / Japanese README documentation

Tech
Next.js, TypeScript, Tailwind CSS, OpenAI API, Vercel, Google AdSense

Architecture

• app/api/analyze/route.ts handles server-side OpenAI requests
• components/chart-upload-panel.tsx manages upload, preview, API call, result rendering, and local history saving
• lib/analysis-history.ts stores completed analysis results in browser localStorage
• components/ad-banner.tsx prepares reusable AdSense-ready ad slots

Links

• Demo: https://chart-insight-assistant.vercel.app
• GitHub: https://github.com/hyeonjo00/chart-insight-assistant
• English README: https://github.com/hyeonjo00/chart-insight-assistant/blob/main/README.en.md
• Korean README: https://github.com/hyeonjo00/chart-insight-assistant/blob/main/README.ko.md
• Japanese README: https://github.com/hyeonjo00/chart-insight-assistant/blob/main/README.ja.md

Service + Chrome extension for tracking Terms of Service and privacy policy updates.

Highlights

• Automatic diff detection
• AI summarization and risk analysis
• Chrome extension one-click workflow

Tech
Next.js, OpenAI API, Chrome Extension (Manifest v3), Vercel

Links

• Demo: https://tos-change-tracker.vercel.app/
• GitHub: https://github.com/hyeonjo00/tos-change-tracker

AI-assisted code review tool for fast quality feedback.

Highlights

• Readability and performance suggestions
• Multi-language code support
• Production-ready review UI

Tech
Next.js, OpenAI API, Tailwind CSS

Links

• Demo: https://ai-code-review-lac-seven.vercel.app/
• GitHub: https://github.com/hyeonjo00/ai-code-review

A premium desktop blackjack simulator built with JavaFX, featuring real-time strategy analysis, advanced gameplay actions, and a casino-style animated UI.

Highlights

• Real-time AI strategy analysis
• Hit / Stand / Double / Split support
• Expected EV, bust risk, and dealer bust chance display
• Session save / load and stats export
• Premium casino-style table UI with animated dealing flow
• Multi-hand split support and recommendation accuracy tracking

Tech
Java, JavaFX, FXML, CSS

Premium Table Theme

Hit / Stand Decision Flow

Double Down Action

Split Hand Management

Premium software engineering whitepapers covering the Blackjack Engine architecture, EV strategy logic, split recursion, UI-state synchronization, and optimization roadmap.

• English Whitepaper PDF
• Korean Whitepaper PDF

Links

• GitHub: https://github.com/hyeonjo00/blackjack-engine-java

A lightweight database management studio built in pure C.

This project combines a reusable storage engine, B+ Tree indexing, WAL-style recovery, and a native raylib desktop UI.

Highlights

• Two-layer architecture with a pure C11 storage engine and a separate native desktop UI
• Hash indexes on id and department, plus B+ Tree indexes on id and age
• Lightweight query optimizer for exact lookups, range scans, and ordered traversal
• CSV snapshot + WAL replay recovery model
• Studio-style desktop workflow with a SQL workspace, result grid, index explorer, storage browser, and performance dashboard

Links

• Repository: https://github.com/hyeonjo00/c-mini-db-engine
• README: https://github.com/hyeonjo00/c-mini-db-engine/blob/main/README.md
• Whitepaper (EN): https://github.com/hyeonjo00/c-mini-db-engine/blob/main/docs/minidb-studio-algorithm-whitepaper-en.pdf