Junhyun An

JUNHYUN AN / PRODUCT ENGINEER

Hello, I'm Junhyun An.

I've worked on web and mobile apps, deployment and service operations.

Selected work in numbers

Client apps built and refined
30
App Store / Google Play releases
10
Planning through deployment and operations
0 to 1
Frontend, backend and infrastructure
End-to-End
View projectsContact
Portrait of Junhyun An

Experience

  1. AppBuildChatLead DeveloperView work
  2. JENTIBackend DeveloperView work
  3. MediologyFull Stack EngineerView work

Work Experience

01

AI MOBILE APP BUILDER

AppBuildChat

Lead Developer 2024.09–2025.12

I refined around 30 client apps and released around 10 to app stores.

I led product planning and task allocation for a team of about five. My work included reviewing AI-generated apps, refining them and handling store releases.

01

Generation workflow

Proposed and specified a workflow that initializes a project and Firebase, then turns a product brief into code.

02

Deployment

Refactored the server and moved it to GCP Cloud Run, improving deployment access, reliability and security management.

03

Shared UI components

Organized Google Material components into a shared library to make generated Flutter apps and subsequent edits more consistent.

04

Clients and releases

Joined client meetings in Canada and India and handled feature checks, signing keys, external builds and App Store / Google Play requirements.

Tech stack
  • Flutter
  • Firebase
  • GCP Cloud Run
  • Mobile Release

02

MOBILE PRODUCT OPERATIONS

Mediology / 신신당부

Full Stack Engineer 2026.06–2026.07

I took over an unfinished React Native app, fixed the app and backend, and deployed it.

I was responsible for the app, backend, admin tools and deployment setup. I also built controls that let operators check service status and change settings.

01

App recovery

Fixed broken social login and other bugs, then reconstructed the existing structure and build process from limited handover information.

02

Admin tools

Built a Next.js dashboard for visits, sign-ups, key user flows, errors and internal data, along with a separate interface for doctors.

03

Data access

Separated user and doctor data in operational views and added server-controlled notices and required-update controls.

04

Release setup

Separated production and test environments and deployed the frontend and backend on GCP. Set up EAS CI/CD and handled recovery of the Google Play upload key.

Tech stack
  • React Native
  • FastAPI
  • Next.js
  • GCP
  • Cloudflare Pages
  • EAS

03

ON-PREMISE AI B2B SAAS

JENTI

Backend Developer 2026.01–2026.05

I developed an AI SaaS backend for enterprise internal networks, including load testing and on-premise deployment.

I worked with other developers on a FastAPI backend. We planned for approximately 1,000 users, and I ran load tests with 50 concurrent requests.

01

Backend development

Worked with FastAPI, PostgreSQL, Redis and Alembic on microservices, gRPC workers and asynchronous processing.

02

Load testing

Tested both bursts of 50 concurrent requests and sustained requests, then adjusted timeouts to the measured server capacity.

03

On-premise deployment

Configured containers in offline Linux environments and worked through enterprise deployment procedures.

04

AI-assisted development

Designed a workflow that reads project conventions and history, breaks work into checklists and keeps implementation and verification consistent.

Tech stack
  • FastAPI
  • PostgreSQL
  • Redis
  • Alembic
  • gRPC
  • Linux
  • Containers

Personal projects

012026—

PERSONAL OPERATING SYSTEM

Life OS

In use · v2 in design

A personal tool for managing projects, schedules and tasks.

View projectSvelteKit · TypeScript
022026—

KNOWLEDGE & AGENT SYSTEM

Second Brain / NERO

In use · Ongoing improvements

A system for recording and searching project conversations and decisions.

View projectMarkdown · Git
032026

INDIE GAME

CLANG! +20

Playable Web Demo

A browser game about upgrading a sword to +20.

View projectReact · TypeScript
042026

OPENAI GAME BUILDERS SEOUL

WUXIA ECHO

Released · Single-player v1

A 3D wuxia strategy game with three movement turns followed by an automatic battle.

View projectTypeScript · Vite

How I work

  1. 01

    Understand the problem

    Find out where users and operators run into difficulties.

  2. 02

    Define the work

    Organize requirements and constraints, then break down the work.

  3. 03

    Build

    Implement and test in small steps.

  4. 04

    Document

    Record the work and the reasons behind decisions.

  5. 05

    Hand over

    Prepare what another person needs to continue the work.

Align requirements

Review the request alongside development constraints and agree on the scope.

Evaluate new technology

Test unfamiliar technology on a small scale before adopting it.

Prepare for operations

Reduce repetitive manual work and document how the service is operated.

Other experience

Repertory

I led the team and built authentication and membership features.

Implemented membership features and native / Google sign-in with Spring Boot, Spring Security, JWT and microservices. Defined service boundaries and restructured log tables.

  • Spring Boot
  • Spring Security
  • JWT
  • MSA

Arts Collective & B-boy

Dance · 10+ Years

I've been a b-boy for over ten years.

Planned and directed performances in an arts collective, working with people from different disciplines to shape the production.

Experience
10+ years
Directed performances
5+
Team size
5–13

AI Workshop

Non-developers · Small Group

I ran practical AI workshops for non-developers.

Explained development terminology and explored ways to apply AI to participants' work through small exercises.

Sessions
3
Participants in total
9
Per session
2–4