HYUNJUNG S&C · EST. 2025 · SOUTH KOREA

Software people use every day.
Next: AI built on Claude.

HYUNJUNG S&C is a South Korean software product company building under the EURION brand. We have shipped four Android apps and two live web services. Next, we are designing AI products to run on Anthropic's Claude API: a retrieval-augmented knowledge engine, a business automation hub, and learning-content intelligence.

Explore Products Partner With Us
  • Built with
  • Flutter · Kotlin
  • Astro · Cloudflare Pages
  • AI-assisted development · Claude Opus 5.5
4
Apps on Google Play
2
Live Web Services
3
AI Products on the Roadmap

Shipped products

Four Android apps (two productivity apps and two games) live on Google Play, and the live ZEKILO web tools: calculators, file tools, and developer tools on one domain, zekilo.com. Each product shows where it actually stands.

Mobile apps & games

4 live on Google Play
LIVE

PushBin - To-dos, Routines & Repeat Reminders

Formerly SalimButton

Check off to-dos for work, study, and home, plus routines like medication, cleaning, and laundry, with a single tap. Repeat reminders, a random task picker, a timer, home screen widgets, and a daily briefing. Your to-dos and history stay on your device.

  • Android
  • Flutter
  • Local-first
  • Widget
  • Free with Ads
PushBin To-dos Details Get it on Google Play
LIVE

Cyber Pinball: Semi Core

A one-hand physics pinball puzzle: launch packets, bounce them off nodes, and catch them again with the moving catcher. 110 circuits across 10 sectors, plus Deep Scan, Infection Alert, and Core Rush. Formerly Chip Match.

  • Android
  • Flutter
  • Flame
  • Physics
  • Offline play
View Details Get it on Google Play

Web services

Tools that run in your browser
LIVE

ZEKILO

Free tools that run in your browser · zekilo.com

Calculators, the Studio file tools, and the Dev developer tools now live together on one domain, zekilo.com, since October 2026. Inputs and files are processed in your browser and never uploaded. Available in English, Korean, and Japanese.

Studio · 22 file tools

Compress and convert images, merge and split PDFs, convert video to MP4, and extract MP3 audio. Contracts and ID scans never leave your device.

Open Studio
Dev · 20 developer tools

Format JSON, decode Base64 and JWTs, encode URLs, test regular expressions, and convert timestamps.

Open Dev
27 calculators

Take-home pay, severance, loan interest, VAT, exchange rates, and floor area, built on Korean and Japanese rules (Korean and Japanese only).

Open calculators (Korean)
  • Web
  • Astro
  • WebAssembly
  • EN · KO · JA
  • Zero Upload
Visit zekilo.com As of 29 October 2026 · The old studio.zekilo.com and dev.zekilo.com addresses redirect to zekilo.com · Its policies are published on zekilo.com.
Private

Internal Operations Platform

A private web application calculating net margins per order and product across sales channels.

Operated internally at sell.eurion.co.kr.

AI PRODUCT ROADMAP

AI products, built for Claude

Two AI products for businesses are in development and a third is planned, all designed to run on Anthropic's Claude API. None is public yet, and Claude API integration is the next step. Each card shows what the product will do.

IN DEVELOPMENT

AI-Powered Knowledge Assistant

An enterprise RAG (retrieval-augmented generation) assistant that will analyze large sets of internal documents and technical data, answer questions in real time, and summarize the insights.

  • Analysis of complex technical documents
  • Vector database search with cited answers
  • Automated business report summaries
IN DEVELOPMENT

Autonomous Workflow & Analytics Agent

An AI agent platform that will automate repetitive workflows and data analysis to support business decisions. It grows out of the margin platform we already run in-house, which calculates net margin per order and product across sales channels.

  • Automated repetitive data processing
  • E-commerce sales and margin analytics
  • Real-time operational monitoring and alerts
PLANNED

Learning & Content Intelligence

Will turn lecture and tutorial videos into material you can search and study. Transcripts will become timestamped notes, and an assistant will answer questions about the video.

  • AI-assisted transcript extraction
  • Jump to the moment a topic is explained
  • A study assistant for each video

Architecture & AI integration

Our planned architecture: all three products will share one pipeline, with Claude as the reasoning layer in the middle of it rather than a chat window added at the end.

  1. 01 · INGEST

    Documents, order and sales data, video transcripts

  2. 02 · INDEX

    Chunking, embeddings, and a vector index

  3. 03 · RETRIEVE

    Hybrid semantic and keyword search, scoped to each customer

  4. 04 · REASON

    Claude API: long-context reasoning and tool use

  5. 05 · DELIVER

    Web dashboards, apps, and APIs, with sources attached

Contextual reasoning with Claude

Claude's long context window will let us pass whole documents, transcripts, or reporting periods in a single request instead of fragments. Tool use will let Claude run multi-step tasks such as querying data, comparing results, and drafting a report, so the products can act as well as answer. We already work with Claude Opus 5.5 every day as an AI pair programmer in our development workflow.

Scalable, privacy-first pipeline

Ingestion, indexing, and reasoning will run as separate services that scale on their own. Each customer's data will be indexed and retrieved only within that customer's workspace. We will carry over the privacy defaults of our shipped apps, which keep user data on the device.

How We Build

Different categories, identical engineering rigor.

Flutter Apps, Static Web

Productivity apps use Flutter with Riverpod and native Kotlin channels, and games use Flame with a physics engine. Web services are static Astro sites running on Cloudflare Pages with no servers to manage.

Local-first Execution

Pushbin notifications and spending records, and PushBin to-dos and history, are stored only on the device and never sent to our servers. The games can be played right away without an account. ZEKILO runs its calculators, file tools, and developer tools in your browser without uploading your inputs or files.

Documented Development

Every release tracks through specifications, architectures, implementation reviews, and automated verification before hitting stores.

Track record

  1. MARCH 2025 · COMPLETED Company founded. HYUNJUNG S&C founded; design of our in-house sales margin system (sell) begins
  2. JANUARY 2026 · LAUNCHED In-house margin system goes live. Our private web system for net margin per order and product across sales channels goes live at sell.eurion.co.kr
  3. 2026 · COMPLETED Pushbin designed and built. Initial product design and Flutter development of the Pushbin notification archive
  4. 2026 · COMPLETED Pushbin spending tracker. Added parsing of payment alerts into a spending log
  5. 2026 · COMPLETED Two mobile games designed and built. Design began in 2026: an idle action RPG and a physics merge puzzle, built with Flutter and Flame
  6. AUGUST 2026 · LAUNCHED Pushbin released. Pushbin launched on the Google Play Store — view on the store
  7. SEPTEMBER 2026 · LAUNCHED Two games released. Chip Match (now Cyber Pinball) and Hacker Cat launched on the Google Play Store — Cyber Pinball · Hacker Cat
  8. 2026 · LAUNCHED SalimButton released and relaunched. SalimButton launched on Google Play, then relaunched with routines, repeat reminders, and a daily briefing as PushBin - To-dos, Routines & Repeat Reminders — view on the store
  9. SEPTEMBER 2026 · LAUNCHED ZEKILO launch. Opened ZEKILO, calculators and converters for users in Korea and Japan — zekilo.com
  10. SEPTEMBER 2026 · COMPLETED AI product planning begins. Started planning a Claude-based knowledge assistant and a workflow and analytics agent
  11. OCTOBER 2026 · LAUNCHED ZEKILO Studio and Dev launch. Opened ZEKILO Studio (upload-free file tools) and ZEKILO Dev (developer tools), then merged them with the calculators under one domain — zekilo.com
  12. IN PROGRESS AI product development. Building the knowledge assistant and the workflow and analytics agent; Claude API integration is the next step

Detailed progress for each product is on the Product Status page.

About HYUNJUNG S&C

Our mission is to build software that solves everyday problems, and to bring practical, trustworthy AI to individuals and businesses.

Contact us About the company
LEGAL ENTITY
HYUNJUNG S&C (현정에스앤씨)
BRAND
EURION
FOUNDED
March 2025
HEADQUARTERS
South Korea
CONTACT
manager@eurion.co.kr
WEBSITE
www.eurion.co.kr