Independent App Developer

I build apps I want to use every day and publish them on the App Store and Google Play. So far that means language learning and workout apps, with more to come.

About PrSeo7

Server & Data Engineering Background

PrSeo7 is a one-person studio. My expertise is in server development, data analysis and data engineering: API design, database architecture and data pipelines built with Node.js and Python.

That background shapes the apps too: they are built on solid, reliable foundations, even when the app itself is small.

Apps Built for Everyday Use

I make apps I need myself, then release them on iOS and Android so others can use them too. The current lineup happens to be language learning and fitness tools, but I am not limited to any one category.

The current portfolio includes JLPT Vocab Master, EasyVocab, ProVocab Advanced and Tabata Timer.

My Apps

JLPT Vocab Master app icon

JLPT Vocab Master

A Japanese vocabulary app by PrSeo7 for JLPT learners: 7,958 words from N5 to N1, studied offline with flashcards and spaced-repetition review. On iPhone, iPad and Android, free with an optional one-time Premium purchase.

  • All five JLPT levels, N5 to N1, in groups of 30
  • Audio for every word and example sentence
  • Meanings in English, Korean or Simplified Chinese
  • Spaced-repetition review
EasyVocab app icon

EasyVocab – English Vocabulary

An English vocabulary app by PrSeo7 for beginner to upper-intermediate learners (CEFR A1–B2): about 6,000 words with flashcards and spaced-repetition review. Listed in Korea as 수능 영단어 – EasyVocab. On iPhone, iPad and Android, free with an optional one-time Premium purchase.

  • 6 levels, 30 words per group
  • Audio for every word and example sentence
  • Example sentences translated into 5 languages
  • Review after 1, 3, 7, 14 and 30 days
ProVocab Advanced app icon

ProVocab Advanced

An advanced English vocabulary app by PrSeo7 for upper-intermediate and advanced learners: 3,781 words at CEFR levels B, C1 and C2, reviewed with spaced repetition. On iPhone, iPad and Android, free with an optional one-time Premium purchase.

  • Pronunciation audio for every word and example sentence
  • English definition and synonyms on every card
  • Translations in Korean, Japanese, Chinese and Spanish
  • Spaced-repetition review
Tabata Timer app icon

Tabata Timer – HIIT Workout

An interval timer app by PrSeo7 for Tabata, HIIT and circuit training. Set your prep, work, and rest durations, then let the countdown beeps guide you through every round. On iPhone, iPad and Android, free with an optional one-time Premium purchase.

  • Customizable prep, work, and rest intervals
  • Countdown beeps for hands-free training
  • Screen stays awake during workouts
  • No account required

Get In Touch

hello.prseo7@gmail.com