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Hello, I’m Gyumin Hwangbo, a backend engineer who designs and automates highly available systems with Spring Boot and Kotlin.

I have worked on projects such as building CDC pipelines that handle thousands of events per second, improving large-scale batch jobs by 95.4%, building per-brand CI/CD pipelines, and designing messaging systems with Redis Streams. My focus is operational automation and maximizing system efficiency.

With the mindset that “every repetitive task should eventually be automated,” I design systems that reduce human intervention in deployment, monitoring, and data synchronization, and that can detect or recover from failures on their own.

EXPERIENCE

  • Backend Engineer (FOODDASH) 2024.04.15 ~ 2025.11.30

    • Developed and operated order, payment, and membership backend services for multi-franchise F&B brands, including Kyochon with 770k MAU, while supporting zero-downtime deployments.
    • Migrated Jadam service data from Wmpo and stabilized operational issues after the service transition.
    • Analyzed bottlenecks in the membership grade renewal batch for 1M+ users and reduced processing time from 19m13s to 53s (95.4% improvement).
    • Separated brand-specific features from shared modules and built an integrated CI/CD pipeline with change-based staging deployments, manual production triggers, rollout tracking, and Slack notifications.
    • Investigated notification loss caused by external Push API timeouts, retries, and server restarts when large notification batches overlapped with real-time order notifications.
      • Served as the technical lead for introducing a Redis Streams message queue to solve notification loss, using Consumer Groups and PEL (Pending Entries List) to provide at-least-once delivery semantics, track in-flight messages, and recover unprocessed notifications after restarts.
      • Stabilized notification loss to near 0% (link).
    • Designed and operated a MySQL CDC -> MQ -> ETL -> MongoDB synchronization pipeline to support fast, large-scale real-time reads by denormalizing read models and reducing multi-query bottlenecks across order and menu tables.
    • Stack: Kotlin, Spring Boot, MySQL, Redis Streams, Kubernetes, AWS

  • Senior Researcher (foxee) 2023.06 ~ 2024.01

    • Built backend APIs for a vulnerability analysis web service with Java and Spring Boot.
    • Conducted CNN/XAI research for malware image analysis and built preprocessing/visualization pipelines for the Windows 2015 malware dataset.
    • Improved the development and deployment workflow with Docker and GitHub Actions.
    • Stack: Java, Spring Boot, PostgreSQL, Docker, Python

  • Intern (Pulse Co., Ltd.) 2020.01 ~ 2020.02 (1 month)

    • Developed internal workflow support tools with Python.

EDUCATION

OPEN SOURCE

ACTIVITIES

  • Patent: Blockchain client vulnerability detection method and device (2022.01 ~ 2022.12)
  • Conference: (NLP) N-gram + threat-actor-based pattern analysis for Windows malware families (2021.12)
  • Software registration: Blockchain-based REC trading platform prototype for RE100 [C-2021-044149] (2021.09 ~ 2021.11)
  • Hackathon: Convergence Security Graduate School Hackathon Competition (2021.09 ~ 2021.11)
  • AI Competition (4th): 2021 Cybersecurity AI/big data challenge, KISA — fileless malware detection (2021.09 ~ 2021.12)
  • Privacy Competition (3rd): 2020 K-cyber security challenge, KISA — privacy (2020.09 ~ 2020.12)
  • Overseas training: San Jose State Univ., San Jose, CA, USA (2019.06 ~ 2019.09)
  • Exchange student: HELP Univ., Kuala Lumpur, Malaysia (2017.12 ~ 2018.03)

CONTACT