Building services that customers actually need
Dohyeon Kim
Software Engineer → Technical Program Manager (8yrs+)
8yr Backend Expert Built and operated high-availability services in Java/Kotlin MSA environments across fintech and e-commerce.
Product-Oriented Drive decisions with data and UX insights, prioritizing business outcomes beyond code.
Cross-Functional Leader Led complex, multi-team programs end-to-end — aligning DBA, data, marketing, compliance, and engineering stakeholders.
Data-Driven Decision Maker Translate structured & unstructured data into actionable business insights and engineering priorities.
Global Communicator 6 years of overseas experience (Sweden). Proficient in English for business communication and cross-cultural collaboration.
01
Professional Experience
Apr 2023 — Present
Server Engineer (3yrs+)
Customer authentication & notification delivery services
- Designed and built a Kafka-based notification delivery pipeline serving millions of customers across push, SMS, and KakaoTalk channels
- Led monitoring system decoupling — coordinated DBA, data, marketing, and dev teams to decouple Hadoop dependency, achieving 24/7 uptime and 80% response time improvement
- Resolved Kafka partition imbalance and introduced reactive consumers, improving TPS from ~400 to ~10,000 (25× throughput gain)
- Rebuilt 30M-record log pipeline with Project Reactor parallelization — processing time reduced from 10 hours to minutes
- Resolved Redis CPU 100% incident by replacing List (O(N)) with Set (O(1)) data structure
- Reduced pipeline creation effort by 80% — proposed and implemented a copy feature based on 1-year log analysis, aligning compliance and operations teams
- Led "My Document Box" integration without PM — achieving 100× subscriber growth (100→10,000/day) through scope negotiation and tech stack decisions
- Developed account-password-based certificate issuance — now ~60% of all certificate issuances
Mar 2022 — Apr 2023
Backend Engineer (1yr)
Customer-facing services: orders, product catalog, reviews
- Improved review service p90 API response from 250ms → 30ms and resolved DB connection pool exhaustion
- Designed and built Style Tab service backend (Clean Architecture + Multi-module) — achieved 30–40% revisit rate (2× industry average)
- Led exhibition system development as PM — designed strategy pattern architecture while managing stakeholders
- Proposed data-driven UX improvements based on Amplitude analysis; adopted by product team
Aug 2018 — Mar 2022
Sr. Backend Engineer (3.5yrs)
Retail product catalog & pricing services
- Designed and developed statistical price anomaly detection system (patented)
- Led retail (Rocket) product catalog service decomposition and system migration
- Designed product modification history architecture and built catalog management back-office
- Led legacy API replacement program end-to-end
- Alternative Military Service as Technical Research Personnel (Oct 2018 — Oct 2021)
02
Selected Projects 2024 — 2026
Program Management & Cross-Functional Leadership
Monitoring System Decoupling — Stakeholder Alignment & Data Governance
TPM · Stakeholder Management
Led a cross-functional initiative to decouple the marketing monitoring system from Hadoop. Coordinated 4
teams (DBA, Data, Marketing Ops, Engineering) to establish data retention policies and a dual-write pipeline
architecture. Translated technical realities into business terms for non-engineering stakeholders,
negotiated trade-offs on data retention scope, and established reusable governance policies.
Monitoring Uptime → 24/7
Response Time −80%
4-Team Consensus
Pipeline Creation Effort Reduced by 80% — Data-Driven Proposal to
Implementation
TPM · Process Optimization
Identified operational inefficiency through 1-year log analysis — 50% of marketing pipelines were repetitive
copies. Proposed a pipeline duplication feature with field-level compliance classification (copy-safe vs.
mandatory re-entry), aligned with Marketing Ops and Compliance teams. Designed within financial regulatory
constraints (audit trail requirements) and implemented end-to-end.
Creation Time: 7.5min → 1.5min
Effort −80%
Compliance-Approved
My Document Box — 100× Subscriber Growth Without PM
TPM · Project Leadership
Led a complex cross-team project without a PM — managing scope, schedule, risk, and stakeholder
communication. Proposed scope reduction strategy ("1-product-first") to mitigate risk, and negotiated a
Backbone WebView → Native implementation switch with client developers. Managed sequential rollout across 7
products.
Subscribers: 100 → 10,000/day
Zero-Bug Deployment
System Re-engineering & Technical Execution
Kafka + Reactive: 30M Log Pipeline Improvement (10hrs → Minutes)
System Re-engineering
Restructured a synchronous 30M-record log pipeline using Project Reactor's Mono.zip for parallel storage
writes. Solved secondary DB connection pool exhaustion via flatMap concurrency tuning and buffer strategy
optimization. Achieved dramatic throughput gains with zero infrastructure cost increase.
Processing: 10hrs → Minutes
No Infra Cost Increase
Kafka Partition Imbalance Resolution & Consumer TPS Optimization
Troubleshooting
Diagnosed StickyPartitioner bug (KAFKA-10888) causing 6:1 partition skew. Applied linger.ms tuning to work
around the bug within Spring Boot 2.7 constraints, and introduced receiveAutoAck for batch-level
acknowledgment — eliminating per-record I/O overhead.
TPS: ~400 → ~10,000
25× Throughput
Redis CPU 100% Incident — Data Structure Optimization (O(N) → O(1))
Incident Response
Identified LREM O(N+M) as root cause of Redis CPU saturation after Kafka TPS optimization. Applied immediate
mitigation (search direction reversal → 50% CPU reduction), then implemented permanent fix by replacing
Redis List with Set for O(1) deletions.
CPU: 100% → ~5%
O(N) → O(1)
Hadoop Dependency Elimination for Marketing Monitoring 100% Availability
Architecture Design
Separated OLAP (Hadoop) and OLTP (MySQL) data sources. Designed dual-write pipeline with data retention
policy (5-day detail + aggregated statistics), enabling marketing operations to monitor independently of the
analytics platform's availability.
Monitoring: 24/7 Uptime
Response −80%
03
Tech Stack
Language
Java
Kotlin
Python
Framework
Spring Boot
Spring Batch
Spring Security
JPA / Hibernate
QueryDSL
JUnit
Testcontainers
Gradle
Database
MySQL
Redis
PostgreSQL
Elasticsearch
Messaging
Kafka
RabbitMQ
Infrastructure / DevOps
AWS
Docker
Kubernetes
GitHub Actions
Jenkins
Collaboration
Git
Jira
Confluence
Notion
04
Education
Jul 2016 — Jul 2018
M.S. in Industrial & Management Engineering
- Industry-academia projects with Hyundai Motors, Samsung Electronics, Samsung Heavy Industries
- Research focus: Data Mining, Process Mining, Anomaly Detection
- Thesis: Multi-perspective Anomaly Detection Using Process Mining
Mar 2012 — Feb 2016
UNIST
B.S. in Computer Science & Technology Management (Double Major)
Sep 2008 — May 2011
Hvitfeldtska Gymnasiet
International Baccalaureate (IB) · Sweden
05
Publications & Patent
Patent — Electronic Device and Method for Providing Product Sales Management
Information
KR Patent KR20220041800A · Apr 2021
Usability of the Size, Spacing, and Operation Method of Virtual Buttons with Virtual
Hand on Head-Mounted Displays
International Journal of Industrial Ergonomics · SCIE · Mar 2020
Modelling the Intrusive Feelings of Advanced Driver Assistance Systems Based on
Vehicle Activity Log Data
International Journal of Automotive Technology · SCIE · May 2019
A Development on a Predictive Model for Buying Unemployment Insurance Program Based
on Public Data
The Korean Journal of BigData · KCI · Dec 2017
06
Activities
Tech Blog
Lectures & Mentoring
Backend Development School — Java Instructor
Mar 2025
ZeroBase
Spring Security Online Course — Instructor
Jul 2024
FastCampus
Capstone Design Mentoring
Mar 2024 — Present
Dongguk University
Backend Online Course — Clean Architecture with Java & Spring
Nov 2022 — Apr 2024
Comento · 10 cohorts mentored
Guest Lectures — Career Talks at Universities
2021 — 2024
Kwangwoon University, Dongguk University, Incheon National University