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Jaeyong Kim (Jay)

Jaeyong Kim (Jay)

Backend & Cloud Architect

+82 50-6661-7806 jaeyong@yshome.me LinkedIn jaeyong.kim

Professional Summary

Backend and Cloud Architect with 11 years of experience, leading business transformations through technical stability and innovation—from 0-to-1 startup builds to post-M&A technical integration (PMI). Led phased serverless migration of acquired assets, driving core migration and carve-out streams to achieve TSA termination. Defended approximately $250K in revenue loss through payment system refactoring. Spearheaded AI technology roadmap design contributing to TIPS program selection. Achieved 35% hardware cost reduction through SaaG protocol design. Possesses exceptional ability to translate technical decisions into tangible financial outcomes and business impact. Pursuing a technology leadership role that accelerates business growth through cloud-native architecture design and legacy modernization, with focus on IoT, Fintech, and Mobility domains.

Key Achievements

M&A Tech Integration (PMI)

Led carve-out migration stream for TSA termination, meeting scheduled TSA deadline.

OpEx reduction & successful TSA termination (AWS Lambda, API Gateway)

IoT Cost Innovation

Designed SaaG protocol based on BLE–HTTPS bridge, eliminating LTE modems in chargers by using smartphones as gateways.

35% hardware BOM reduction & communication cost elimination (BLE, Merkle Tree, Python)

Fintech System Stabilization

Analyzed payment bottlenecks and introduced Django + Celery async queue with idempotency design, reducing batch payment processing time by 94%.

Payment processing time reduction, ~$250K unpaid collection recovery (Django, Redis, Celery)

Platform Engineering

Introduced Terraform-based IaC and ArgoCD ApplicationSet to standardize infrastructure provisioning and deployment, significantly reducing deployment lead time.

Deployment standardization & lead time reduction (EKS, Terraform, ArgoCD)

Security & Integrity

Designed data integrity verification system capable of operating in unstable network conditions, reliably managing data inconsistency cases during operations.

Data integrity verification (Cryptography, SQS, S3)

Core Skills

Cloud & Networking

Multi-Account environment governance, heterogeneous infrastructure integration through VPN routing optimization, hybrid cloud network design.

Platform Engineering

GitOps pipeline enhancement on AWS EKS, resource optimization via Karpenter and Spot instances, Terraform-based IaC.

System Architecture

Phased serverless transition, distributed transaction management and idempotent payment system design, high-performance async messaging architecture.

Backend Engineering

High-availability API design with Python (Django, Ninja), Node.js, Java (Spring Boot), and internal common module (NPM/PIP) distribution system establishment.

Leadership

Engineering culture and technical standards establishment, M&A technical integration, contribution to government R&D (TIPS) and MS Launcher program selection (secured ~$400K Azure credits).

Work Summary

Work Experience

Pluglink – Tech Lead

Mar 2025 — Aug 2025, EV charging platform, Founded 2021, Private, ~$15M revenue scale, 30 employees

Mission: Integrate heterogeneous IT infrastructure acquired from Hanwha Solutions and terminate high-cost TSA (Transitional Service Agreement) in short term to secure operational efficiency and technical independence.

Achievements

  • Successful TSA Termination through Phased Serverless Migration: Deployed API Gateway in front of legacy monolith to control traffic and progressively separated core functions to AWS Lambda-based serverless. Led core technical migration plan and carve-out stream targeting TSA termination, contributing to on-schedule operations transfer and technical independence.
  • Complex Network Environment Optimization: Resolved connectivity issues between public institutions (KECO) and acquired business units through integrated VPN routing changes, eliminating network conflicts and securing stable integration.
  • OCPP Messaging Bridge Layer Operations & Stabilization: Operated and managed WebSocket-based OCPP messaging pipeline, reviewing and improving bridge layer message transformation/routing logic and DynamoDB-based connection state management flow. Separated and organized SNS/SQS-based message pipeline by domain to ensure consistent processing and operational stability in high-traffic environments.
  • Engineering Standardization & Operations Improvement: Operated and improved common module/DTO reuse system using internal NPM registry to enhance development productivity. Maintained Jenkins pipelines, Slack notifications, and EKS manifests to standards, strengthening deployment procedure consistency and automation level.
Tech Stack
AWS Lambda Serverless Framework API Gateway Java (Spring Boot) Node.js TypeScript Python DynamoDB SNS/SQS RDS Elasticsearch Datadog Jenkins GitHub Actions.
Reason for Leaving: After successfully completing PMI and initial stabilization mission, organization transitioned to maintenance phase. Strategically moved to pursue new challenges where advanced architecture design capabilities could be better utilized.

Pierrot Company – CTO

May 2024 — Mar 2025, Electronics subscription service 'phoneGO', Founded 2019, Private, ~$1.5M revenue scale, 10 employees

Mission: Resolve revenue leakage from payment failures, design technology roadmap for government support program (TIPS) selection, and secure business scalability through architecture modernization.

Achievements

  • Idempotency-based Bulk Payment System Refactoring: Analyzed bottlenecks and failure rates of existing synchronous payment processing and redesigned to Django + Celery-based async queue structure. Applied idempotency keys and exponential backoff (Smart Retry) logic, reducing batch payment processing time from 3 hours to 10 minutes, preventing duplicate payments and recovering revenue loss through ~$250K unpaid collection.
  • IaC & GitOps Enhancement: Codified entire infrastructure with Terraform (IaC) achieving 100% reproducibility. Introduced ArgoCD ApplicationSet reducing deployment lead time by 76% (30 minutes to 7 minutes).
  • Platform Engineering & Resource Optimization: Achieved 25% infrastructure cost reduction through Karpenter and Spot instance-based EKS node configuration, and unified deployment specs through Helm chart standardization.
  • CS Operations Efficiency & Automation: Built Kakao notification automation module to eliminate manual response work, significantly reducing CS team workload and improving operational accuracy.
  • R&D Strategy & Funding: Led 'Used electronics rental demand prediction AI engine' technology roadmap design, contributing to TIPS program selection and government R&D funding acquisition.
Tech Stack
Python (Django/DRF) Celery Redis React TypeScript Kubernetes (EKS) Terraform ArgoCD GitHub Actions PostgreSQL Datadog Prometheus Karpenter.
Reason for Leaving: After completing core missions including TIPS selection and payment system stabilization, accepted Pluglink's recruitment offer to experience larger scale and traffic in the EV charging platform domain.

Chain Lightning Company – CTO & Co‑founder

Nov 2021 — May 2024, EV charging & mobility super app 'Sparkle', Founded 2021, Private, Early revenue stage, 10 employees

Mission: Build EV charging platform from 0 to 1 as early-stage startup, technically solve hardware cost and communication fee burden to secure sustainable business model.

Achievements

  • SaaG (Smartphone-as-a-Gateway) Protocol Design: Designed BLE–HTTPS bridge utilizing smartphones as gateways, eliminating LTE modems in chargers. Secured business scalability through ~35% hardware BOM reduction and monthly communication cost elimination.
  • Offline-First Security Architecture Design: Designed Rolling Key encryption and Merkle Tree-based integrity verification protocol for unstable network environment response, ensuring data consistency and security.
  • Large-scale Public Data Pipeline & Recommendation Engine: Built multi-threaded KECO public data collection pipeline, implemented route optimization recommendation algorithm using PostGIS and MiniBatchKMeans.
  • Real-time Communication & Fintech Domain: Built real-time chat system with Django Channels + Redis Pub/Sub + MongoDB storage. Established payment/coupon/point consistency management system through wallet (Deposit/Withdraw) modeling.
  • Generative AI Service Pivot: Led GPT-based D.PILOT (legal work copilot) and AI travel/companion platform Tripmate development from 2023. Led 8-person team to MVP launch in 2 weeks.
  • Technical Business Achievements: MS Launcher selection (up to ~$400K Azure credits), Seoul Creative Economy Innovation Center Pre-startup Package excellent completion, Credit Guarantee Fund NEST 12th, D.CAMP D.DAY, K-Global SNU Unicorn Acceleration and multiple accelerating programs selection contribution.
  • Full-stack Product Development & Operations: Designed and implemented login/payment/coupon/wallet systems, real-time chat, notification/file management modules. Built GitHub Actions-based CI/CD, Docker Compose and AWS ECS/Fargate deployment pipelines, chat system using MongoDB, Redis Pub/Sub, and Django Channels.
Tech Stack
Python (Django Ninja) Flutter AWS ECS/Fargate GitHub Actions PostgreSQL (PostGIS) MongoDB Redis Redis Pub/Sub Django Channels New Relic Firebase Microsoft Azure.
Reason for Leaving: As founder, successfully executed 0→1 phase innovation and multiple pivots, but business closed due to market conditions. After organizing technical assets, accepted Pierrot Company's CTO offer to exercise capabilities in professional organization.

Additional Experience

Education

Military Service

Industrial Technical Personnel (Alternative Military Service, Completed) Dec 2018 — Oct 2021

Certifications

Languages

Selected Activities