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ethan-k/README.md

Hi there, I'm Eunseok Kang πŸ‘‹

LinkedIn Email Location

πŸš€ About Me

Versatile and results-driven full-stack engineer and tech lead with over 10 years of experience building scalable, production-grade systems. Proven ability to ship quickly in fast-moving environments, with deep expertise in backend (Java, Go, Kotlin) and frontend (React, TypeScript) development.

  • 🌱 Strong track record in leading teams, designing distributed architectures, and optimizing CI/CD pipelines
  • 🎯 Led engineering initiatives that improved user connection rates by 20% and reduced API costs by 20%
  • 🌍 International experience across South Korea, Germany, Singapore, and Japan
  • ☁️ Expert in cloud migration from on-premises to AWS and Kubernetes infrastructure

πŸ› οΈ Tech Stack

Programming Languages

Java Go Kotlin Python PHP TypeScript JavaScript

Frontend

React Next.js Redux React Native

Backend & Frameworks

Spring gRPC

Cloud & Infrastructure

AWS Kubernetes Docker Terraform Helm

Data & Messaging

MySQL PostgreSQL MongoDB Redis Apache Kafka RabbitMQ Amazon SQS Apache Airflow Snowflake

DevOps & CI/CD

GitHub Actions GitLab CI Jenkins Ansible

πŸ’Ό Professional Highlights

🏦 Banksalad (May 2022 - Aug 2025) - Senior Software Engineer (Tech Lead)

  • 🎯 Performance Optimization: Cut external data-provider API costs by 20% via multi-layer caching
  • πŸ“ˆ Architecture Leadership: Led MyData 2.0 redesign, raising connection success by 20%
  • πŸ”„ System Resilience: Led transition from synchronous to asynchronous data sync for improved resilience
  • ☁️ Cloud Migration: Led migration initiatives from on-premises to AWS and Kubernetes
  • πŸ‘₯ Team Leadership: Led 3-person engineering team, introducing Agile and mob programming practices
  • ⚑ Scale: Built large-scale Go microservices on MySQL databases exceeding 4TB
  • πŸ—οΈ Systems Design: Built data sync systems with Go, gRPC, MySQL, AWS SQS/SNS, Kafka, and Redis

πŸ‡ΈπŸ‡¬ Facebook (Oct 2019 - Dec 2020) - Software Engineer in Test Infrastructure (Contract)

  • πŸ§ͺ Test Automation: Developed automated test failure analysis systems for improved debugging
  • πŸ“Š Testing Velocity: Established pipelines for test automation and result analysis
  • πŸ”§ Framework Enhancement: Enhanced internal E2E testing framework with Jest, TypeScript, React, Hack, and Python

πŸ‡ΈπŸ‡¬ Gojek (Nov 2018 - Oct 2019) - Software Engineer in Financial Department

  • πŸ’° Financial Platform: Developed financial platform using Spring (Java), Go, React (TypeScript), PostgreSQL, and BigQuery
  • πŸ—οΈ Microservices: Designed and implemented distributed systems with microservice architecture
  • πŸ“Š Data Systems: Developed high-throughput data distribution system using Kafka and Go

πŸ‡―πŸ‡΅ Rakuten (Apr 2017 - Sep 2018) - Software Engineer in Travel Department

  • ✈️ Travel Platform: Developed travel itinerary system for Japan's second-largest travel booking platform
  • πŸ”§ CI/CD: Established deployment pipelines using Jenkins, Ansible, and shell scripts
  • πŸ§ͺ QA Enhancement: Created test data comparison application using React

🌟 Open Source Contributions

Keycloak Terraform Provider

Active contributor to the official Keycloak Terraform Provider with 4 merged PRs:

  • #1381 - Added authentication subflow data source
  • #1323 - Added support for sub mapper configuration
  • #1382 - Fixed PKCE code challenge method state persistence
  • #1391 - Added missing authorization resource documentation

Contributions span documentation improvements, bug fixes, and feature additions, improving the infrastructure-as-code experience for Keycloak users worldwide.

🎯 Key Achievements

  • πŸ“Š 20% Cost Reduction in external data-provider API calls through multi-layer caching optimization
  • πŸ“ˆ 20% Improvement in connection success rates through MyData 2.0 architecture redesign
  • ⚑ 40% CI/CD Optimization of GitLab pipeline through architectural improvements
  • πŸ—οΈ Migration Leadership from on-premises to AWS Cloud and Kubernetes infrastructure
  • πŸ”§ Full-Stack Expertise across backend (Java, Go, Kotlin), frontend (React, TypeScript), and cloud infrastructure
  • 🌐 Global Impact with experience across 4 countries (South Korea, Germany, Singapore, Japan) and multiple industries (fintech, travel, social media)
  • πŸ’Ύ Large-Scale Systems handling 4TB+ MySQL databases in microservices architecture
  • πŸ” Enterprise Authentication designed company-wide SSO solutions with advanced access control

πŸ“ˆ GitHub Stats

GitHub Stats

πŸ“« Let's Connect!

I'm always interested in discussing technology, architecture, and engineering leadership. Feel free to reach out!

Pinned Loading

  1. cachemanager-go cachemanager-go Public

    Cache Manager in Go

    Go

  2. bazel-spring-boot-kotlin bazel-spring-boot-kotlin Public

    Bazel example for Spring boot with kotlin

    Starlark

  3. pomodoro-cli pomodoro-cli Public

    Go 1

  4. terraform-provider-keycloak terraform-provider-keycloak Public

    Forked from keycloak/terraform-provider-keycloak

    Terraform provider for Keycloak

    Go