Backend Developer & DevOps Engineer from South Korea, with experience across NHN Cloud, Samsung Electronics, Nexon Korea, and Dongbu CNI.
I enjoy building reliable backend systems, cloud-native infrastructure, and deep observability stacks that actually survive production traffic.

• Java / Kotlin (Spring Boot, MVC, WebFlux)
• Node.js / TypeScript / JavaScript
• C++ (IOCP, high-performance networking)
• SQL & NoSQL (Oracle, SQL Server, MySQL, Cassandra, Redis)

• AWS (EC2, RDS, Lambda, Route53, NLB/ALB, S3, ACM, CloudFront, CloudWatch)
• Infrastructure as Code (Terraform)
• CI/CD with Jenkins, CircleCI
• Docker & docker-compose

• Grafana · Prometheus · Loki · Jaeger · Mimir · Cortex - Fluentd · Telegraf · Consul

Java 17 · Spring Boot 3 · MVC · Oracle · MyBatis · JWT Security · Swagger

A production-like backend service with:

• JWT authentication (/api/v1/auth/login)
• RESTful APIs for user, service management
• Oracle DB integration through MyBatis
• Optimized Oracle schema with structured table design, indexing strategy, and query performance tuning
• docker-compose support for local Oracle + MinIO
• OpenAPI docs included

🔗 https://github.com/choiis/Spring-WebServer-Oracle

TypeScript · Node.js · Serverless Image Processing · AWS Lambda · S3 · SNS · CircleCI

A Lambda that resizes images instantly on S3 uploads:

• TypeScript + serverless-framework
• SNS notification after resizing
• CI/CD pipeline using CircleCI
• AWS X-Ray for tracing and debugging

🔗 https://github.com/choiis/ImageResizer_AWS_Lambda

Kotlin · Spring WebFlux · Cassandra · Zookeeper · Grafana Mimir

Distributed monitoring system designed for large-scale black-box checks:

• API & TCP scenario workers running in parallel
• Measures DNS lookup, TCP connection, network latency
• Cassandra as metadata/config DB
• Zookeeper for distributed coordination and locks
• Metrics exposed to Prometheus/Mimir

🔗 https://github.com/choiis/black-monitoring-watcher

Terraform IaC · Multi-tier AWS Architecture

Defines a complete AWS environment through code:

• VPC, subnets, routing tables, NAT/IGW
• EC2 (bastion, app servers), RDS, Redis
• NLB + Route53 + ACM + Autoscaling Group
• Security Groups and IAM roles
• Architecture design included in Draw.io format

🔗 https://github.com/choiis/AWS-terraform

C++ IOCP Chat Server · SQL Server · Jenkins Pipeline

High-performance chat system:

• IOCP-based chat server, bot client, and console client
• SQL Server storage (schema included)
• Jenkinsfile for automated Windows builds
• Visual Studio project (x64, Release)

🔗 https://github.com/choiis/Cpp-IOCP-Server

Full Observability Stack · docker-compose

All-in-one monitoring lab:

• Grafana Mimir (long-term metrics)
• Prometheus (scraper + remote-write)
• Loki (log aggregation)
• Jaeger (distributed tracing)
• Consul (service discovery)
• Everything runs via docker-compose up

🔗 https://github.com/choiis/Grafana-Mimir-Loki-Jaeger

• Java, Kotlin, C++
• JavaScript / TypeScript
• SQL (Oracle, SQL Server), CQL (Cassandra)

• Spring Boot, WebFlux, Security, Batch
• MyBatis
• Node.js (Express)
• jQuery
• serverless-framework

• Maven, Gradle, Ant

• Oracle, SQL Server, Cassandra, Redis
• MinIO, AWS S3

• AWS (EC2, RDS, S3, Lambda, CloudFront, Route53, ACM, ELB, CloudWatch)
• Terraform (HCL)
• Docker & docker-compose
• Kafka, Zookeeper
• Consul

• Git, GitHub, GitLab, SVN

• Jenkins, CircleCI, GitHub Actions

• Grafana, Prometheus, Loki, Jaeger, Mimir, Cortex, Consul, Fluentd, Telegraf

• Continuous learning of modern Java, Spring Boot, and Kotlin technologies
• Multi-VPC AWS architectures with Transit Gateway
• Migrating legacy backends to Java 17 / Spring Boot 3 / Kotlin
• Efficient relational database schema design and high-performance SQL tuning
• Deep observability pipelines (metrics + logs + traces)
• Serverless event-driven services

• GitHub: https://github.com/choiis
• Location: South Korea