Minsik Lee — Backend / Full-Stack Engineer

Seoul, South Korea · heiminsik@gmail.com · github.com/dldl8819

Backend-leaning full-stack engineer with 5+ years of professional experience, 4 of them in software development, across financial, manufacturing, and public-sector systems. Java/Spring Boot and React/TypeScript on Linux and Docker. Consistently the person who takes an intermittent production failure and finds the actual cause — container networking, repository integration, request-path behavior — instead of patching the symptom. Currently completing a 400-hour AI agent development program (FastAPI, SQLAlchemy, LangChain).

The rest of this site is written in Korean. This page is the English summary.

Selected Strengths

• Root-cause debugging. Traced an intermittent connection failure, with nothing in the application logs, to a Docker network CIDR collision using packet and routing analysis, then restored TCP flow with a static route. Pinpointed where artifact ingestion from a Nexus Repository silently failed by comparing success and failure logs stage by stage, and handed the finding to the headquarters developer who fixed the product code.
• Reviewing code for what it leaks, not just what it returns. Framework defaults are frequently unsafe: a FastAPI validation error echoes the submitted request body, including the password, so I replaced it with a handler that returns field names only. Applied the same review habit to HTML escaping of database-sourced values and to auth errors that reveal whether an account exists.
• Verifiable documentation and tests. Wired JUnit test results into Spring REST Docs so API documentation fails the build when behavior changes. Maintain detailed public engineering notes explaining design decisions and failure analysis.

Experience

MPC Plus — Engineer, DT Division

2026.04 – 2026.06 · Contact-center (AICC) platform development and operations

• Analyzed CTI and WebSocket real-time messaging flows and stood up the development environment.
• Built JSP/Vue.js screens, PostgreSQL/PostgREST services, OpenResty proxying, and n8n automation.

Cudo Communication — Engineer, AX Service Development

2024.05 – 2026.03 · Operations and maintenance of an open-source vulnerability management system at two financial institutions (a bank and a life insurer)

• Worked on site at client institutions: analyzed client requests, changed Java (Spring Boot) business logic and React screens, and deployed the fixes.
• Ran routine server checks and handled day-to-day contact with client staff.
• Handled incident response on Docker/Linux, including the two incidents described above (Docker CIDR collision, Nexus ingestion failure).

Nuriggum Soft — Engineer, DX Development

2023.08 – 2024.04

• Automated REST API documentation with JUnit and Spring REST Docs, so documentation is only generated when tests pass.
• Applied and verified a Single Message Transform for Oracle-to-Kafka change data streaming at a card issuer.
• Built web screens for an MSA-based manufacturing operations system for a steel manufacturer.

Esum Tech — Engineer, Service Development

2022.05 – 2023.05 · EAI integration delivery and maintenance

• Delivered EAI-based web systems for a public quarantine agency, a retail/IT enterprise, and an agricultural distribution body (Java, JSP, jQuery, Tibero, AIX, AWS).
• Analyzed cross-system interfaces and data structures to resolve integration defects.

LB Hunet — Technical Support, Technical Team

2020.08 – 2021.08

• Diagnosed internet, IPTV, and IoT faults for a telecom carrier’s customers, narrowing causes through structured elimination and explaining them in plain language.

Technical Skills

Area	Stack
Languages	Java, TypeScript, JavaScript, Python, SQL
Backend	Spring Boot, FastAPI, JSP, REST API design
Frontend	React, Next.js, Vue.js
Data	PostgreSQL, Oracle, MySQL/MariaDB, Tibero, MongoDB, Kafka, Snowflake
Infrastructure	Docker, Linux (CentOS/Rocky), Nexus Repository, Git, SVN
Testing / Docs	JUnit, pytest, Spring REST Docs
Integration	EAI, WebSocket

Side Project

Heifam — team-balancing and match-record service for a StarCraft community, built solo and running in production. Next.js/TypeScript front end, Spring Boot API, Supabase (PostgreSQL). Evaluates every possible team combination to minimize rating gap, updates ratings with an ELO algorithm from match results, and derives per-player and per-composition statistics. (source)

Education & Certifications

• Hanwha Tomorrow Academy — AI Agent Service Development, 400 hours (2026.09 – 2026.11, in progress)
• Jeonju University — B.A. in English Education, double major in Counseling Psychology (2020)
• SnowPro Core (2025) · MongoDB Certified Associate DBA (2024) · MongoDB Certified Associate Developer (2024)

Languages & Availability

Korean (native). English: intermediate — comfortable reading technical material and writing code reviews and documentation.

Available as a remote contractor on flexible hours, based in KST (UTC+9).