정재철

RESUME

Jaecheol Jeong

Backend Engineer

Seoul, South Korea · anjwoc@gmail.com

EmailGitHubLinkedIn
An engineer deeply interested in improving work environments and automating development processes using AI. Experienced in handling large-scale traffic in B2C commerce and ad domains, as well as designing AI Agent-based legacy analysis and frontend workflows. Passionate about identifying inefficient processes and actively introducing new technologies to boost team productivity. Recently designed and implemented an AI Agent workflow for automatic documentation of legacy systems using MCP and a Playwright QA automation pipeline. Beyond just writing code, I am a solution-oriented engineer who strives to pioneer an "AI-based smart work environment" so that teams can focus on more valuable work.

AI-based Workflow Improvements

Designed AI Agent-based workflows to reduce repetitive development, analysis, and QA work while improving team onboarding into complex systems.

  • Code Sonar — AI-based Legacy System Analysis Plugin Design
    • Built an evidence-based system documentation flow connecting GitHub, Jira/Wiki, and MSSQL to reduce legacy onboarding friction
  • AI Agent Dev & Playwright QA Automation
    • Automated the issue-level QA validation pipeline by combining Figma/spec-driven frontend development with auto-generated and executed Playwright E2E tests

Work Experience

Gmarket

Seoul, South Korea
MarTech Engineering · Backend Engineer
2026.05 ~ Present
💡 B2C Affiliate System & AIDC Integration Project
  • B2C Affiliate System Development
    • Participating in early planning and design for a new AIDC-integrated affiliate system

Gmarket

Seoul, South Korea
AdTech Engineering Team · Backend Engineer
2023.01 ~ 2026.05
💡 AdTech Team at Gmarket, 6M MAU Commerce Platform — Full CPC Ad System
  • Responsible for the entire CPC ad system on the AdTech engineering team at Gmarket, a commerce platform with 6M MAU
  • CPC Ad Ranking Performance Optimization
    • Reduced ranking refresh time from 4 hours to 3 minutes, cut CPU usage by 60%, and stabilized peak traffic handling
  • Cross-DB Data Sync Pipeline
    • Ensured MS-SQL↔MongoDB consistency without commercial CDC, reducing operational risk from data mismatches
  • CPC Ad Data Migration to Databricks
    • Moved Hadoop-based batch workflows to Databricks, reducing recurring manual reprocessing
  • EDN+ Server Rebuild
    • Rebuilt the Node.js legacy server in Spring and stabilized ad serving for Karrot and Danawa placements
  • ATS Migration
    • Upgraded Node.js v6 to v16, moved to Kubernetes, and introduced Datadog monitoring
  • Display AD Video Product
    • Added video ad support to the image-focused legacy ad system and contributed to a new ad product launch
  • AIDC Ad Center Frontend Architecture
    • Led Next.js · React architecture and key screen development for the new ad center
  • PowerClick Admin Development & Operations
    • Improved promotion, bidding, ad group, creative, and budget management features
Spring BootWebfluxRedisKafkaMongoDBNode.jsExpress.jsDatabricksOpenshiftKubernetes

Catenoid

Seoul, South Korea
Convergence Team · Backend Engineer
2021.02 ~ 2022.11
🎬 #1 B2B Video Solution in Korea — 500+ Clients, 100Gbps Daily Traffic
  • #1 B2B video solution provider in Korea, ~500 domestic and international clients, daily traffic of 100Gbps
  • Loomex Media Distribution Enhancement
    • Migrated from .NET monolith to Node.js MSA and introduced event-driven architecture
  • VOD & Live Streaming Process Enhancement
    • Added multi-engine processing and serverless workflows to optimize operations cost
  • Social Media Syndication Feature
    • Reduced a 6-step manual YouTube/Facebook setup to one-time OAuth authentication
  • Resumable Large-file Chunk Upload
    • Improved large-file upload reliability with chunking and resume support
  • Deployment Automation
    • Built GitHub Actions + Jenkins pipelines for environment-specific deployments
Node.jsExpress.jsNest.jsSpring BootAWSWowza Streaming EngineAWS MediaLive

WineSoft

Seoul, South Korea
Platform Team · Full-stack Developer (Node.js & Vue.js)
2020.04 ~ 2020.09
⚡ B2B Solution Company — STON Edge Server · M2 Image Engine
  • B2B solution company developing STON Edge Server (high-performance cache) and M2, an image generation engine
  • M2 Engine Parser Development
    • Built a URL-based image transformation spec parser; passed 11st Q/A and deployed to production
Vue.jsNode.jsExpress.js

Computer Science Lab

Asan, Chungnam
Undergraduate Lab · Undergraduate Researcher
2018.03 ~ 2019.02
  • Assisted graduate student research and performed related development
  • Developed a Python module to receive sensor data and index it into Elasticsearch
  • Participated in a blood glucose prediction research project; performed ML data preprocessing
  • Indexed and visualized data using Elastic Stack (Elasticsearch, Logstash, Kibana)
PythonElasticsearchLogstashKibana

Skills

Backend
Spring BootSpring WebfluxNode.jsExpress.jsNest.js
Database
MongoDBMS-SQLRedisElasticsearch
Messaging
KafkaAWS SQSAWS EventBridge
Infra / Cloud
AWSKubernetesOpenshiftDockerDatabricks
Monitoring
DatadogCloudWatchKibana
Frontend
Vue.jsReactTypeScript
DevOps
GitHub ActionsJenkinsCI/CD

Education

Soonchunhyang University

2014.03 ~ 2020.02
Computer Science and Engineering

Certificates

AWS Developer Associate
2021.12.13 · 2140803
Engineer Information Processing
2019.08.16 · 19202050968K