Deokhwan Kim
Resourceful problem solver · Product engineer
What I can take on
Backend engineer who treats the service and the infrastructure under it as one system — I find problems in invoices, metrics and query plans, and fix them so they can be rolled back.
- Product discovery, customer interviews, MVP scope, and full-stack implementation.
- Cloud infrastructure, deployment, observability, recovery, and code-review systems.
- Agent orchestration with explicit ownership, validation gates, and human review boundaries.
Selected evidence
- AgentGram: 881 organization-wide merged pull requests; 789 were merged by the autonomous pipeline I designed and operate. The figure measures system throughput, with authorship distributed across autonomous work and review.
- Fleet operations: 45 scheduled jobs and 383 completed kanban cards.
- log8.kr: 61 hand-written blog posts, 100 agent-published Library posts, and 2 guides.
- GitHub stars: agentgram 32 and ax-score 3.
Projects
PurplePepper — AWS cost optimization, observability for ~400 servers, service migration
2026.03 — Present | Backend & Infrastructure (5-person dev team)- Overturned my own "CPU-only" lane rule with controlled experiments: the 16GB boxes were bound by memory (swap), so cutting lanes 14% raised throughput 13%; a separate rendering-setting experiment cut per-item processing time (Takt Time) by 41%.
- Found and fixed a backup guard silently reporting "backup ok" daily (cleared 232GB of stale WAL archives, disk 75%→24%); folded the fix into the shared template to block the same failure elsewhere.
- With Cost Explorer unavailable on the account, broke the raw invoice down myself and removed idle servers, oversized tasks and unused reserved capacity — an estimated ~$1.5k/month (~18% of the bill); the August batch is confirmed on actual invoices (−$917/month on the affected services).
- Added a missing index to a query that scanned all 22 partitions on every call: buffer reads 132,542 → 66, worst case 23.6 s → ~0.04 s.
- Migrated Supabase to NestJS + AWS (ECS Fargate) with Terraform-based blue-green deployment; replaced long-lived IAM keys with GitHub OIDC; staging deploy 21 min → 22 s.
- Rolled out log/metric collection to ~400 self-hosted servers (rollback path first), removed a watchdog with 87k false alarms and 0 true detections, and traced the cause of 31 DB restarts.
- Zero-downtime legacy migration (39 caller accounts unchanged, one-line rollback, 38K requests/day).
- Converted the overnight batch platform (8 boxes, 64 lanes) to OS-level self-healing — 490K+ jobs/night at 98.4% success, including Mac/Linux fleet + AWS setup.
Shipped the Nyangmoney reward app on iOS — designed a B2B2C user-acquisition channel
2026 — Present | Product & engineering (iOS shipped, Android closed beta)- Built an independent reward app to solve the company's B2B2C cold start (needing advertisers and users at once) via a dedicated acquisition channel.
- Designed an ad-consuming reward loop so a user pool forms before advertisers are signed, reversing the usual sequencing.
- Shipped to the iOS App Store; resolved native social-login issues on real devices while running Android closed beta.
- Next.js + Capacitor single codebase across web/iOS/Android.
- Supabase + Firebase (FCM, Admin) for auth/push/data, with AdMob ad-reward integration.
- Native Google/Apple social login and an asset pipeline for app store review.
Built GCP infrastructure and established team code review as Backend Lead
2025.12 — Present | Backend Lead (5-person backend team)- Raised review frequency 400% (about 5×).
- Reduced Terraform-based recovery from 56h to 5h.
- Scripted the rebuild path for an estimated about 2h next lead time.
- Java 21, Spring Boot 3.4, MySQL, QueryDSL.
- Terraform + GCP infrastructure as code.
- CI/CD, VPC, separated dev/prod databases, rollback deployment.
Designed and ran AgentGram's autonomous contribution pipeline
Until Sept 2026 | Pipeline designer and operator- The Hermes multi-agent pipeline (retired Sept 2026) autonomously implemented, reviewed, and merged 789 of 881 organization-wide pull requests; branch protection and CI gates kept autonomous merges safe.
- Kanban-based autonomous decision-making decomposed the backlog and assigned tasks without human intervention — only irreversible calls escalated to a human approval gate.
- Review-gated autonomous work across a multi-repository ecosystem.
- Next.js 16, TailwindCSS v4.
- Supabase (PostgreSQL + RLS), API-first architecture across core/JS/Python/MCP/AX repos with Ed25519-signed identity.
- Self-hosting, Docker, REST API, OpenAPI.
Won the ICAN-LABs top award with a 40-interview MVP
2025.09 — 2025.12 | Solo full-stack developer, frontend-led- Cut mathematics-content production time to 1/10.
- Identified tool complexity through 40 interviews.
- Used a 5-week I-Corps-based validation sprint.
- Next.js, MathJSON, Fabric.js, JSXGraph.
- Formula parsing and geometry visualization engine.
- MVP prototyping and user testing.
Tech Stack
LanguagesTypeScript, Java, Python, C++
FrontendNext.js, Astro, React, TailwindCSS
BackendSpring Boot, NestJS, Supabase
DatabasePostgreSQL, MySQL, pgvector
DevOpsAWS (ECS Fargate, ECR), GCP, Terraform, Docker, Cloudflare Tunnel, GitHub Actions, Sentry, tmux
AI Orchestration Lab
- Runs Claude Code, Codex, and agy (Gemini) concurrently via OMC/OMX-driven Loop Engineering (generate → test → verify) to ship fully verified work.
- Measured 5× learning efficiency and 10× development speed after the workflow shift (vs. January 2026).
- Hermes fleet (retired Sept 2026): ran 24/7 on a single Mac mini with 45 scheduled jobs and 383 completed kanban cards, atomic claim → isolated workspace → written handoff.
- Autonomous work it handled: automated blog publishing, GA data analysis, YouTube video production and upload, and AgentGram's autonomous development and QA.
- Irreversible work stops at a human approval gate, so autonomy and safety hold together.
Experience
UMC 9th Cohort — Web Part Lead (teaching and mentoring), Spring Boot challenger
2025.09 — PresentUMC 8th Cohort — Web challenger (React, Next.js)
2025.03 — 2025.08Practical AI lectures — senior small-business owners
2025.05, 07Practical AI lecture — Re:ium founders (MCP, agent AI)
2025.09Awards & Certifications
Awards
Certifications
Education
Chung-Ang University2020.03 — 2026.08
- Mathematics (primary major) / Software & Humanities Convergence (double major).
- Completed the teaching curriculum (Level 2 Secondary School Teacher Certificate).
- 162 credits completed; GPA 3.86/4.5.