Hi, my name is

Rhosung Park.

Full-stack engineer & startup CTO.

I design, build, and ship web and mobile products end-to-end — from Postgres schemas and REST APIs to React Native apps in the App Store. Most recently CTO at FitlyEver, a Korean-market fitness startup.

View my workGitHub
Portrait of Rhosung Park

01.

About

I'm a software engineer based in Southern California who likes owning products across the whole stack. Over the last few years I've shipped production mobile apps to the iOS and Android app stores, built and deployed the backends behind them, and led a small engineering team as a startup CTO.

At FitlyEver, a Korean health-tech startup, I was the sole author of the backend and co-built our gamified fitness app across three product generations — nutrition tracking with barcode scanning, AI consultations, in-app subscriptions, and maps. Outside of work I build and operate HIS App, a church community platform serving 50+ active users since 2023, and I'm currently prototyping RoomLift, an AI interior-improvement app.

I hold a B.A. in Computer Science and Psychology from Brandeis University, and I bring a design background to engineering — I'm an Adobe Certified Associate and comfortable in Blender and the full Adobe suite, which shows up in the UI polish of everything I ship.

By day, I build enterprise software at Tata Consultancy Services.

Currently working with

  • ▹TypeScript
  • ▹React / Next.js
  • ▹React Native / Expo
  • ▹Node.js / Express
  • ▹Supabase
  • ▹PostgreSQL
  • ▹Tailwind CSS
  • ▹Python

02.

Experience

  1. 2021 — Present

    Software Engineer — Intel Team @ Tata Consultancy Services

    USA

    Embedded with Intel, building internal technology solutions that Intel Business Development Managers use to advise customers across cloud, CPU, and AI.

    • ▹Built a Cloud Instance Modernization tool that helps BDMs identify and recommend modern Intel-based cloud instance types for customer workloads.
    • ▹Developed an On-Prem to Cloud Migration Recommendation Engine guiding customers' migration paths from on-premises infrastructure to the cloud.
    • ▹Delivered a range of internal tooling spanning cloud, CPU, and AI initiatives in support of Intel's business development organization.
    CloudAI/MLPythonTypeScript

  2. 2024 — 2025

    CTO & Co-founder @ FitlyEver

    Remote (Korean market)

    Led engineering at FitlyEver, a Korean-market health-tech startup whose main product is 핏리에버 — a gamified fitness and nutrition mobile app: meal logging via search and barcode scanning, AI-powered consultations, body-metrics tracking, a points and rewards system, facility discovery on Naver Maps, and RevenueCat-managed subscriptions. The product codebase is private (business repository).

    • ▹Led a three-person engineering team from prototype to a published iOS/Android app across three product generations.
    • ▹Built the food database behind meal logging: FatSecret API integration plus a self-built Python crawler for Korean packaged products, searchable with Korean-romanization handling and camera barcode scanning.
    • ▹Sole author of the backend: an Express + TypeScript REST API over Supabase/Postgres with PLpgSQL migrations, Swagger-documented and deployed serverless on Vercel — auth, FatSecret food-search integration, barcode lookup, meal tracking, and AI-consultation endpoints, built in a two-week sprint.
    • ▹Co-built the Expo/React Native app: migrated the entire data layer to TanStack React Query with custom hooks, and built barcode food entry, custom-food CRUD, body-metrics tracking, subscription and payment verification, data export, and the Naver Maps location stack with reverse geocoding.
    • ▹Owned production infrastructure: EAS builds and OTA updates, a Storybook + Chromatic component workshop, and a custom pre-commit linter enforcing design tokens and dark-mode coverage.
    • ▹Re-architected the codebase into a Turborepo/pnpm monorepo with 14 shared packages, implementing Kakao and Supabase ID-token auth, session persistence, and onboarding in a four-day sprint.
    • ▹Built the supporting toolchain, including a Next.js CRM with a drag-and-drop Kanban dashboard.
    TypeScriptReact NativeExpoSupabasePostgreSQLExpressNext.jsTurborepoRevenueCatVercel
    fitlyever.com ↗

03.

Projects

HIS App (히즈앱)

2023 — Present

A live church community platform serving 50+ users since 2023

A full community platform for Inland HIS Ministry that I built and operate solo — up and running in production with 50+ active users: a native mobile app for iOS and Android plus a public website. Members get a home feed, events with RSVP, weekly bulletins, polls, small-group spaces, an in-app Bible reader with a reading challenge, and push notifications — with staff managing everything through in-app admin screens gated by role-based permissions.

  • ▹Evolved through three architectures over three years — Flask + AWS with a Streamlit admin console, then an Expo + Supabase v1, then a clean v2 rewrite (200+ commits) that shipped to the app stores.
  • ▹Supabase backend: Postgres with extensive PLpgSQL migrations, Auth (Apple, Kakao, email OTP), Storage, and Edge Functions for FCM push notifications and YouTube content ingestion.
  • ▹Membership approval workflow and granular role-based permissions power in-app management of users, ministries, and small groups.
  • ▹Ships continuously: EAS builds with OTA updates across dev/preview/production environments, plus a Next.js public website.
React NativeExpoTypeScriptSupabasePostgreSQLReact QueryZustandNativeWindNext.js
Website

RoomLift

2026 — Present

AI-powered room improvement — snap a photo, get a better room

A cross-platform app that analyzes a photo of your room with OpenAI vision models and returns taste-aware improvement suggestions, matched against a curated product catalog and monetized through Amazon Associates and Impact.com affiliate links — designed around real affiliate-program compliance constraints from day one.

  • ▹OpenAI vision analysis with structured outputs drives room understanding and personalized, taste-aware recommendations.
  • ▹Supabase Edge Functions (Deno) and Postgres with row-level security power the catalog, secrets, and affiliate-link sync.
  • ▹One Expo codebase ships to iOS, Android, and web.
ExpoReact NativeTypeScriptOpenAI APISupabasePostgreSQLDeno

비밀우체국 (Secret Post Office)

2026 — Present

Location-based letters you discover by walking there

A poetic take on social: write a letter under a pen name and leave it invisibly at a physical spot — others discover it only by walking there, guided by a compass. Letters cluster on a dark city map, travel on journeys carried by walkers, and step tracking ties the experience to real movement. Fully bilingual (Korean/English).

  • ▹Mapbox-powered map with custom glow markers, clustering, and a compass screen that points you toward nearby hidden letters.
  • ▹Real-world movement as a mechanic: pedometer and health-API step tracking with an odometer, plus location-anchored letter placement.
  • ▹Supabase backend with React Query data layer, pen-name identities, letter inbox, and shareable polaroid-style cards via view-shot.
ExpoReact NativeTypeScriptMapboxSupabaseReact Queryi18next

Musee

2023 — 2024

Online art gallery delivering the story behind every artwork

An art-tech product built with a co-founder: an Angular PWA where collectors discover, rate, and view artworks in AR, with community verification voting and price/worth estimation charts — later pivoting toward auctions with a FastAPI backend rewrite and a virtual-exhibition showcase site.

  • ▹Angular 15 PWA with AR viewing, masonry discovery feed, artwork rating, and Chart.js price-worth visualizations.
  • ▹Flask + SQLAlchemy + Postgres + Redis backend (Dockerized), rewritten in FastAPI with JWT auth for the bidding pivot.
  • ▹Shipped a waitlist landing page and an Angular 17 virtual-exhibition marketing site.
AngularFlaskFastAPIPostgreSQLRedisDocker
GitHub

Other noteworthy projects

CoB Transparency

2020

Senior field study with Boston's Office of New Urban Mechanics: a public map of IoT sensors collecting data around the city, making municipal data collection transparent to residents. I designed the UI/UX, built the frontend, and liaised with the city's point of contact.

RailsMapbox GLLeafletBootstrap

Rate My Professor @ Brandeis

2020

Full Rails + Postgres platform for Brandeis students: professor reviews, search, a "Match Me" course matcher, Ask-and-Advise Q&A, and an admin dashboard. I worked full-stack and designed the review database schema.

Ruby on RailsPostgreSQL

Moim

2020

Cross-platform college community app — courses, assignments, grade calculator, and notifications — built with Flutter and Firebase (Auth, Firestore, Google Sign-In). I drove development full-stack, designed the visual identity, and supervised the team's git and NoSQL workflow.

FlutterDartFirebaseFirestore

Dusty

2020

Air-quality tracker built twice: first as a Node/Express web app with charts, then rebuilt native with React Native, geolocation, Redux Toolkit, and Firebase auth.

React NativeRedux ToolkitFirebaseNode.js

Amy

2024

A demo that turns spoken commands into device actions: browser speech recognition streams to a Flask-SocketIO backend that uses OpenAI as a natural-language-to-command parser.

PythonFlaskSocketIOOpenAI API

Portfolio CMS

2021

An earlier personal site built as a full product: Angular SPA frontend plus a Node/Express/MongoDB backend with OAuth-protected admin panel, blog post CRUD, and project management.

AngularNode.jsExpressMongoDB

04.

Skills & Open Source

Core stack

TypeScriptReact / Next.jsReact Native / ExpoNode.js / ExpressSupabasePostgreSQLTailwind CSSPython

Frontend & mobile

ReactNext.jsReact NativeExpo RouterAngularFlutterNativeWind / TailwindStorybook

Backend & data

ExpressFlaskFastAPIRuby on RailsPostgreSQLRedisFirebaseApache Spark / Scala

Infra & tooling

VercelAWSDockerTurborepoEAS Build / OTASwagger / OpenAPIGitHub ActionsAdobe CC / Blender

Open-source contributions

  • ▹

    react-native-kakao-login — patched the library's iOS Expo config plugin to fix Kakao sign-in in Expo prebuild workflows.

  • ▹

    SparkTaskMetrics — extended Databricks' Task Metrics Explorer — upgraded Spark/Scala versions and added Catalyst-optimizer details to task-level metrics.

  • ▹

    flutter_rounded_date_picker — forked and patched the date-picker plugin to fit Moim's custom theming.

05. What's next?

Get in touch

Whether you have a project in mind, a role to discuss, or just want to say hello — my inbox is always open.

Say hello