zunDev Studio

Independent software studio

Thoughtful software.
One product
at a time.

Mobile apps for vocabulary learning, community Bible reading, and casual games. Built with care, from the first idea to release.

View selected work Get in touch
Independent by design.Explore the products

01 / Selected work

Ideas, becoming products.

Mobile software for learning, shared routines, and a little play. Here’s what’s taking shape.

Language learningPreparing for release

VocaMint

A little play.
A lasting vocabulary.

Short, game-like English vocabulary sessions with automatic review. Built for TOEIC and TOEFL learners.

  • Flutter
  • Dart
  • Riverpod
  • SQLite

The product, in practice

  1. 01

    Make it a short session.

    A focused learning loop designed for mobile.

  2. 02

    Play with the words.

    Game-like interaction and text-to-speech bring vocabulary into practice.

  3. 03

    Come back to what matters.

    Automatic review helps keep previous words in the learning routine.

Under the surfaceLocal learning progress, text-to-speech, and automatic review, with release testing across the learning flow.

Community & reading

Bible Reading

In development

A shared reading rhythm. A community-focused app bringing reading plans, progress, and reflection into one place.

Product focus
Group reading campaigns, calendar-based progress, notes, and highlights.
Being built
Backend integration, authentication and account lifecycle, group nudges, and notification preferences.
  • Flutter
  • Dart
  • Supabase
  • PostgreSQL
  • OAuth
  • Storage
Mobile casual game

Yacht Dice

Preparing for distribution

A classic, carefully made. Yacht dice gameplay with responsive interaction, clear decisions, and attention to the details that make play feel right.

Product focus
CPU gameplay, dependable game state, and a responsive interface for iOS and Android.
Release quality
Release testing covers gameplay, UI behavior, and reduced-motion accessibility.
  • Flutter
  • Dart
  • iOS
  • Android
  • Automated testing

In the studio

Currently building.

  • VocaMint

    Preparing the first production release.

  • Bible Reading

    Building backend integration and the community reading experience.

  • Developer infrastructure

    Improving AI-assisted development and QA workflows.

02 / Engineering

How products get built.

The interface is only the beginning. Equal care goes into the systems behind it and the work needed to ship.

01 — Shape

Start with the useful part.

Turn an idea into a focused product flow. Build mobile interfaces around clear interactions, readable content, and accessible behavior.

02 — Build

Make the pieces work together.

Cross-platform Flutter and Dart, deliberate state management, and backend integration. Connect authentication, data models, and storage to the product experience.

03 — Validate

Treat release as part of the work.

Review changes, test behavior, and check real device layouts. Keep accessibility, edge cases, and iOS and Android release preparation in the loop.

AI-assisted development

AI-assisted.
Engineer-reviewed.

Claude is part of the workflow for architecture exploration, repository-level reasoning, implementation, code review, and debugging.

It also supports test generation and review, documentation, and release preparation. AI speeds up iteration; engineering decisions are reviewed, tested, and validated.

03 / The studio

Small studio.
Real products.

zunDev Studio is an independent software studio based in South Korea, focused on building useful mobile products.

Founded and operated by Junseo Lee, a software developer working across mobile engineering and AI-assisted development. A small practice with hands-on involvement from the first product decision to release preparation.

Junseo Lee Founder & developer

04 / Get in touch

Good products start
with a conversation.

Product questions, developer conversations,
or something worth building.

Founder & program enquiries