Jaemyeong Jin.

Software Engineer · 9+ years experience · South Korea

Résumé version

A software engineer with more than nine years building Apple-platform products and expanding into AI-assisted development, web, and backend services.

  1. 01

    9+ years building, shipping, and improving Apple-platform products

    • Favorie, Sendy, Goodoc, and Coupang Play
    • iOS, iPadOS, and tvOS development in Swift and Objective-C
    • Sendy’s new-app design and launch as sole iOS developer; Coupang Play’s new sports calendar
  2. 02

    AI agents in development and verification

    • AI agents, self-hosted CI, and Codex adversarial review in the Swift Registry development loop
    • Development and verification loop combining AI agents with GitHub Issues
  3. 03

    Expanding into web, backend, and SaaS

    • Web and app development with TypeScript, React, and React Native (Goodoc)
    • SwiftPM supply-chain SaaS with Swift 6 and Vapor (Swift Registry)
    • Multi-tenant platform with NestJS, FastAPI, Next.js, and Supabase (Nutrition Engine)
Summary

More than nine years designing, shipping, and improving Apple-platform products with Swift and Objective-C across iOS, iPadOS, and tvOS. Product work at Favorie, Sendy, Goodoc, and Coupang Play; recent expansion into AI-assisted development and verification, web, backend, and SaaS. Sendy’s new-app design through launch, CI/CD, and payment integration as its sole iOS developer; Coupang Play’s sports calendar in its universal iOS and iPadOS app. AI agents, self-hosted CI, and Codex adversarial review in Swift Registry’s development loop. Continued expansion grounded in Apple-platform experience.

Experience

2016.12 – 2026.04
2023.07 – 2026.042 yr 10 mo

Coupang

Senior iOS Software Engineer

Core sports experiences in Coupang Play’s universal iOS and iPadOS app; network and list-infrastructure improvements.

New builds

  • Build the sports calendar in the universal iOS and iPadOS app
  • Introduce the Sports Pass subscription flow on tvOS
  • Add live-chat message reporting and user blocking

Improvements and modernization

  • Revamp the discover feed and league pages
  • Implement the BottomSheet component and Animator

Operations and collaboration

  • Add an analytics pipeline and NewRelic logging

New builds

  • Build the sports calendar in the universal iOS and iPadOS app
  • Implement bidirectional infinite scrolling, league filters, and empty/error states
  • Introduce the Sports Pass subscription flow on tvOS
  • Add live-chat message reporting and user blocking
  • Implement the tvOS Double Badge live-dot animation, focus handling, and cache lifecycle
  • Add 4K/HDR quality badges across iOS, iPadOS, and tvOS

Improvements and modernization

  • Revamp the discover feed and league pages
  • Migrate 8+ endpoints to a URLSession-based network module; adopt async/await
  • Move 5+ modules to Compositional Layout and Diffable Data Source
  • Implement the BottomSheet component and Animator
  • Move Firebase dependencies from CocoaPods to JFrog
  • Rewrite per-sport statistics in SwiftUI; add personalized score hiding

Operations and collaboration

  • Add an analytics pipeline and NewRelic logging
  • Replace 2023 app-rebrand assets

Projects

  • Sports domain overhaul

    Built the sports calendar for the universal iOS and iPadOS app, including bidirectional infinite scrolling, league filters, and empty and error states. Revamped the discover feed and redesigned the league page.

  • Legacy modernization

    Migrated more than eight endpoints to a URLSession-based network module with async/await. Moved more than five modules to Compositional Layout and Diffable Data Source, and migrated Firebase dependencies from CocoaPods to JFrog.

  • Apple TV (tvOS) expansion

    Implemented live-dot animation, focus handling, and cache lifecycle for the tvOS Double Badge system, and introduced the Sports Pass subscription flow. Added 4K/HDR quality badges across iOS, iPadOS, and tvOS.

  • Live-chat safety

    Introduced message reporting and user blocking across iOS and iPadOS. Implemented BottomSheet and Animator components and applied them to the related experiences.

  • Sports detail · analytics · rebrand

    Rewrote per-sport statistics for iOS and iPadOS in SwiftUI and added a personalized hide-scores feature. Expanded the analytics pipeline with NewRelic logging and replaced assets for the 2023 app rebrand.

Technologies

Swift · SwiftUI · Combine · Diffable Data Source · Compositional Layout · async/await · URLSession · JFrog · NewRelic

2022.05 – 2023.071 yr 3 mo

Goodoc

Frontend Engineer

Customer-facing hospital booking and mobile check-in plus an operations back office; about 80,000 bookings in the first six months after launch.

New builds

  • Build booking and check-in tabs, a date-picker calendar, and forms in TypeScript, React, and React Native
  • Build an operations back office
  • Develop the main home tab in the core team

Improvements and modernization

  • Separate business logic from the main home tab

Operations and collaboration

  • Improve iOS-native modules; handle App Store releases and incident response
  • Transfer app ownership
  • Oversee code reviews and conventions as app maintainer

New builds

  • Build booking and check-in tabs, a date-picker calendar, and forms in TypeScript, React, and React Native
  • Build an operations back office
  • Develop the main home tab in the core team

Improvements and modernization

  • Separate business logic from the main home tab
  • Increase daily reviews by roughly 100 through a unified review flow

Operations and collaboration

  • Improve iOS-native modules; handle App Store releases and incident response
  • Transfer app ownership
  • Oversee code reviews and conventions as app maintainer

Projects

  • Booking & mobile check-in

    Built booking and check-in tabs, a date-picker calendar, forms, and an operations back office in TypeScript, React, and React Native. The service processed about 80,000 bookings in its first six months, and daily reviews increased by roughly 100 after the review flow was unified.

  • Mobile app home

    Developed the main home-tab components in the core team and separated business logic to improve the structure.

  • iOS-native & app maintainer

    Improved iOS-native modules, handled App Store releases and incidents, transferred app ownership, and served as an app maintainer overseeing code reviews and coding conventions.

Technologies

TypeScript · React · React Native · iOS

2020.08 – 2022.031 yr 8 mo

Sendy

iOS Developer

New-app architecture, development, launch, CI/CD, and payment integration as Sendy’s sole iOS developer.

New builds

  • Design and ship the new app with MVVM-C
  • Integrate Naver Pay, Kakao Pay, and NicePay

Improvements and modernization

  • Migrate from RxSwift to Combine
  • Switch CI/CD from GitHub Actions to Xcode Cloud
  • Modernize the legacy Isamoa app

Outcomes

  • iOS development during a period of 100%+ growth in delivery requests

New builds

  • Design and ship the new app with MVVM-C
  • Integrate Naver Pay, Kakao Pay, and NicePay

Improvements and modernization

  • Migrate from RxSwift to Combine
  • Switch CI/CD from GitHub Actions to Xcode Cloud
  • Modernize the legacy Isamoa app
  • Consolidate Isamoa’s mixed Objective-C and Swift code around Swift; move MVC to MVVM
  • Separate Isamoa’s network layer with Moya; overhaul the UI

Outcomes

  • iOS development during a period of 100%+ growth in delivery requests

Projects

  • Sendy (freight app)

    Designed, built, and shipped the app as the sole iOS developer. Applied MVVM-C, migrated from RxSwift to Combine, moved CI/CD from GitHub Actions to Xcode Cloud, and integrated Naver Pay, Kakao Pay, and NicePay. Owned iOS development during a period when delivery requests grew by more than 100%.

  • Isamoa

    Solely took over a stalled legacy app. Consolidated a mixed Objective-C and Swift codebase around Swift, migrated MVC to MVVM, separated the network layer with Moya, and completed a full UI overhaul.

Technologies

Swift · RxSwift · Combine · MVVM-C · Moya · GitHub Actions · Xcode Cloud

2016.12 – 2020.043 yr 5 mo

Favorie

Developer

Healthcare, scheduling, and video-filter iOS apps; Objective-C modernization toward Swift and MVVM.

New builds

  • Build healthcare, scheduling, and video-filter iOS apps

Improvements and modernization

  • Modernize Objective-C code toward Swift and MVVM
  • Use Apple frameworks including HealthKit, Core Motion, iCloud, AVFoundation, and Core Image

Web

  • Develop Pathfinder with Vue, Nuxt, Apollo, CircleCI, and AWS ECS

New builds

  • Build healthcare, scheduling, and video-filter iOS apps
  • Vivace: step tracking with HealthKit and Core Motion; REST layer
  • AT: Today Extension widget and themes; iCloud sync and backup
  • Cliplog: camera control and video capture with AVFoundation; Core Image filters

Improvements and modernization

  • Modernize Objective-C code toward Swift and MVVM
  • Use Apple frameworks including HealthKit, Core Motion, iCloud, AVFoundation, and Core Image

Web

  • Develop Pathfinder with Vue, Nuxt, Apollo, CircleCI, and AWS ECS
  • Build Nuxt.js SSR, an Apollo GraphQL API server, and zero-downtime deployment with CircleCI and AWS ECS

Projects

  • Vivace

    A healthcare app applying behavior-change techniques. Tracked steps with HealthKit and Core Motion, built a REST layer, and migrated from Objective-C to Swift while adopting MVVM.

  • AT

    A scheduling app that visualizes time as a graph. Migrated from Objective-C to Swift and built a Today Extension widget, themes, and iCloud sync and backup.

  • Pathfinder

    A coworking-space website and admin system. Used Vue.js and Nuxt.js SSR, an Apollo GraphQL API server, and zero-downtime deployment with CircleCI and AWS ECS.

  • Cliplog

    A video-filter app. Controlled the camera and recorded video with AVFoundation, applied filters with Core Image, and designed an MVVM structure.

Technologies

Swift · Objective-C · HealthKit · Core Motion · iCloud · AVFoundation · Core Image · Vue.js · Nuxt.js · Apollo GraphQL · AWS

Side Projects

Released · iOS

Nine - Block Puzzle

Native iOS game · offline play

Grand-prize winner of the 5th Bu:Star Challenge Game Contest.

Implementation

  • Build the board, piece dragging, and animation directly in UIKit with no game engine
  • Keep the install under 10 MB; size varies by device

Integrations

  • Integrate two Game Center leaderboards

Usability

  • Run fully offline without an account, sign-in, or server

Implementation

  • Build the board, piece dragging, and animation directly in UIKit with no game engine
  • Keep the install under 10 MB; size varies by device

Integrations

  • Integrate two Game Center leaderboards
  • Integrate a remove-ads in-app purchase and UMP consent flow

Usability

  • Run fully offline without an account, sign-in, or server
  • Support dark mode, a left-handed layout, and separate sound and haptic settings
Released · web and mobile

DailySudoku

Shared domain engine · cross-platform CI/CD

One deterministic Rust engine for puzzle generation, validation, state transitions, and scoring across Android, iOS, and Web.

Build

  • Connect the engine to each platform with UniFFI and wasm-bindgen

Verification and delivery

  • Validate Rust, Wasm, UniFFI, Android, iOS, and Web in a seven-job CI pipeline

Build

  • Connect the engine to each platform with UniFFI and wasm-bindgen
  • Automate four Android ABIs, a three-slice iOS device/simulator XCFramework, and WebAssembly packaging

Verification and delivery

  • Validate Rust, Wasm, UniFFI, Android, iOS, and Web in a seven-job CI pipeline
  • Set up OIDC-based S3/CloudFront web delivery, a Play internal track, and Xcode Cloud iOS packaging
Private beta · in progress

Swift Registry

SwiftPM supply-chain SaaS · AI-assisted development

Private-beta registry SaaS for immutable, auditable Swift Package artifact delivery.

Build

  • Implement SE-0292 reads and SE-0391 publishing with Swift 6 and Vapor
  • Use SHA-256 content addressing and conditional S3 writes

Development and verification

  • Integrate AI agents, self-hosted CI, and Codex adversarial review into the development loop

Build

  • Implement SE-0292 reads and SE-0391 publishing with Swift 6 and Vapor
  • Use SHA-256 content addressing and conditional S3 writes
  • Implement fail-closed archive validation and organization-level authorization and audit

Development and verification

  • Integrate AI agents, self-hosted CI, and Codex adversarial review into the development loop
  • Pair AI agents with GitHub Issues in the development and verification loop
Private beta · in progress

Nutrition Engine

Entity-resolution RAG · provider-grounded nutrition

Entity-resolution RAG for Korean food aliases using pgvector embeddings, with nutrient values from public data records.

Build

  • Search food aliases with 1,024-dimensional embeddings and pgvector HNSW
  • Limit the LLM to food identification and normalization; use MFDS, USDA, and Open Food Facts records for nutrient values

Build

  • Search food aliases with 1,024-dimensional embeddings and pgvector HNSW
  • Limit the LLM to food identification and normalization; use MFDS, USDA, and Open Food Facts records for nutrient values
  • Build a multi-tenant platform with NestJS, FastAPI, Next.js, Supabase RLS, REST, and MCP
Released · macOS

Storage Game

1.44MB Game Contest entry · one floppy disk

Signed and notarized app bundle within the 1,474,560-byte capacity of a 3.5-inch floppy (777,100 bytes currently).

Implementation

  • Draw every visual and synthesize every sound in code with no image or audio assets

Game

  • Build eleven merge tiers from an 8-inch floppy to an NVMe SSD

Implementation

  • Draw every visual and synthesize every sound in code with no image or audio assets
  • Build an Apple silicon and Intel universal binary

Game

  • Build eleven merge tiers from an 8-inch floppy to an NVMe SSD
  • Implement real-time matches by random pairing or five-character room code, plus an anonymous-callsign leaderboard

Distribution

  • Complete single-player without a network
  • Share one backend and wire format across Mac App Store and itch.io builds

Education

Kyungsung University · B.S. in Computer Science

Military Service

Republic of Korea Army · Sergeant, honorable discharge

Awards · Certifications

  • 5th Bu:Star Challenge Game Contest — Grand Prize
  • 1st Busan Mobile App Contest — Grand Prize
  • Engineer Information Processing
  • Industrial Engineer Information Processing
  • Craftsman Programming

Skills

Apple platforms
iOSiPadOStvOSmacOSSwiftObjective-CUIKitSwiftUICombine
Web and cross-platform
TypeScriptJavaScriptReactReact NativeKotlin
Backend and AI
VaporNode.jsRAGpgvectorAI Agents
Infrastructure
AWSDevOpsGit
Technologies explored
RustUniFFI

Contact · Links

Emailjaemyeong@me.com