SJ System
Developer and operator of STAYTOQ, our own AI SaaS

We connect AI to real work.

WHAT WE BUILD

What we do: Industry AI Services, Custom Systems, AI Diagnosis & Training

SJ System is an AI solutions development and implementation company that improves how businesses work with AI and software. We built STAYTOQ, an AI chatbot for lodging businesses, and run it as a live service.

Start a project

First consultation is free · No obligation to proceed

Mission

We give our customers their time back.

AI takes on the repetitive work, so people can spend their time on what only people can do.

Read our mission and vision →
SJ System in 28 secondsOur three businesses, the STAYTOQ hospitality AI chatbot and its live production metrics — what SJ System does, in 28 seconds (in Korean).
// 01 — credentials
16 years
Enterprise system development experience

Designed and built systems including emart24's ERP and POS, the Korea Forest Service's ‘Supnadeul-e’, Starbucks mobile, and an AI help desk for a large enterprise.

Live in production
STAYTOQ, our own AI chatbot SaaS

Since launching in May 2026, it has handled 2,718 inquiries in total at real lodging properties.

Mail-order business registration
No. 2026-Goyang Deogyang-gu-1374

Our own payment system, StayPay, meets the requirements to process bookings, payments and refunds directly.

// 02 — ax-consulting
AI Transformation Diagnosis & Training

We start by finding where AI should actually be used.

AX (AI transformation) is not about adding a chatbot. It starts with finding where your time is being lost today, then deciding which of that work to hand to AI and which people should keep doing.

At SJ System, one team takes it all the way — from that diagnosis to building the system and operating it after launch.

CONTINUOUS LOOPSTEP 1DiagnoseSTEP 2DesignSTEP 3BuildSTEP 4Verify
Once results are verified, we find the next transition point and diagnose again. We don't build once and walk away.
  1. STEP 1

    Operations Diagnosis

    We break your day down hour by hour. Using real data, we check what inquiries come in and how many, where they repeat, and at what times they are being missed.

  2. STEP 2

    Transformation Design

    We separate what AI will take over, what the system will automate, and what people need to keep doing. We don't push to switch everything to AI — we tackle the highest-impact items first.

  3. STEP 3

    System Development

    We build it ourselves — AI chatbots, admin systems, reservations and payments, and websites. Because the team that designed it also develops it, requirements don't get lost in handoffs.

  4. STEP 4

    Results Verification

    We measure success not by how many features we shipped, but by how many hours we gave back. Response volume, response rate and time saved are checked in numbers every month.

It doesn't end with a report

Consulting that diagnoses and leaves only hands the owner more homework. With us, the people who run the diagnosis build the system, and the people who build it operate it to the end. We don't outsource or subcontract.

Yangju JamJam Glamping & Caravan

A case that began with an AI transformation diagnosis and continued through system development. We moved the time tied up in repetitive inquiries and scattered channels over to AI, and brought reservations, settlement and cleaning schedules together in a single admin system, improving operational efficiency and productivity.

38.5 hrs
Response time saved per month
770 chats
Auto-replies per month
96.4%
AI response rate
See case studies →
More about AI diagnosis & training →
// 03 — services

What we do

We help companies with AI transformation (AX) in three ways: we build industry AI services, build business systems for each company, and run diagnosis and training to set the direction for AI adoption.

  1. 01Problem DiscoveryProblem discoveryFind problems that keep coming up in diagnosis, training and custom-build work.
  2. 02PrototypeBuild small and fast to confirm the problem really gets solved.
  3. 03PilotApply it at a real customer site and validate it in operation.
  4. 04ReferenceCreate the first success story, proven in numbers.
  5. 05ProductRefine a solution built for one place into a product many customers use.
  6. 06SaaSOffer it as a service, from sign-up through billing and operations.
  7. 07Next VerticalNext verticalTake the proven approach to find problems in the next industry.
Industry AI Services

Industry AI Services

We solve recurring problems in the field with products. Every industry handles customers, information and daily work differently — we build and run AI services that fit each industry's workflow and get used every day.

  • STAYTOQ — an AI service connecting customer support and operations for lodging businesses, live
  • Rank Tracker — a monitoring service that tracks Naver Place keyword rankings, beta
  • Media Vault — a media asset management system for content search and controlled external sharing, in development
  • Next industry — turning problems proven in the field into services for the next industry
Learn more →
Custom AI & Business Systems

Custom AI & Business Systems

We build around the way your company works. We develop the AI features you need for customer support, internal knowledge search and repetitive work, build web, app and internal business systems, and connect the tools and data you already use.

  • AI support — organize recurring customer inquiries and connect them to follow-up work
  • Internal knowledge search — find company documents scattered across places right when you need them
  • Workflow automation — connect the information people keep re-typing and moving by hand
  • Web, apps and internal systems — web, apps and admin systems that fit how you work (CallPop, Goeunheuk, StayPay)
  • Existing tool integration — connect the tools and data you already use to new features
Learn more →
AI Transformation · Diagnosis & Training

AI Transformation Diagnosis & Training

We help you decide where to apply AI and put it to use on the job. We look at the work that takes the most time and the problems that keep recurring, set priorities by impact and feasibility, and support adoption with an action plan and hands-on training.

  • Work analysis — see in real work where time goes and problems arise
  • Priority setting — decide what to solve first by impact and feasibility
  • Action plan — lay out the data needed, development scope and rollout order
  • Hands-on training — teach staff to use AI in their own work
Learn more →

Our technologies

See our business structure →
// 04 — ai-team

AI Development Team

At SJ System, one CEO works alongside a team of AI teammates.

Assistant, developer, marketing and accounting AI each take on a role and handle real work, and nothing is applied until the CEO has reviewed and approved it. We bring the same way of working we use every day to client projects.

Jiheung Jeong, CEO of SJ System
CEO, SJ System · Full-stack & AI developer, 16 years

Jiheung Jeong

I spent 16 years building enterprise systems. Now I use the same approach to help small businesses.

Meet our CEO →

Assistant AI

Claude Sonnet

Takes the CEO's instructions, breaks them into tasks, assigns them to the right AI, and reports on progress.

  • Breaks instructions received over chat into task cards
  • Assigns the responsible AI · sets priorities
  • Reports progress and completion

Developer AI

Claude Opus

Writes the actual code according to assigned task cards. Works in an isolated workspace, and changes are applied only after the CEO reviews and approves them.

  • Writes and modifies code based on task cards
  • Works in an isolated workspace without touching production code directly
  • Shows changes to the CEO and applies them only after approval

Marketing AI

Claude Sonnet

Drafts Instagram card news and newsletters to promote STAYTOQ. Nothing is published without the CEO's approval.

  • Plans and drafts Instagram card news
  • Drafts newsletters
  • Publishes only after CEO approval

Accounting AI

Claude Sonnet

Records revenue and expenses, tracks receivables, and summarizes and reports the financial position.

  • Records revenue and expenses
  • Tracks receivables and confirms payments
  • Monthly financial summary reports

Every AI teammate's output passes through a CEO approval gate — no AI deploys or publishes anything on its own.

// 05 — production-metrics

Proven in production

Real results from building and operating our own AI chatbot, STAYTOQ, for Yangju JamJam Glamping & Caravan (as of August 2026).

The live Yangju JamJam Glamping & Caravan website with the STAYTOQ AI chat window open
The STAYTOQ AI chat window running today on the Yangju JamJam website — a real, unedited screen.See it live on the Yangju JamJam website ↗
staytoq — production metrics

$ staytoq metrics --tenant yangjujamjam --month 2026-08

  • Auto-replies in August770 chats
  • AI response rate96.4%
  • Response time saved in August38.5 hrs
  • In the knowledge base448 Q&As

# source: live operating data from Yangju JamJam Glamping & Caravan (August 2026)

$

See case studies →
// 06 — latest-build

Latest project

Website Development · STAYTOQ AI Chatbot

Goeunheuk (Pure Raw Red Clay Manufacturing & Supply)

SJ System planned, designed and developed the website for Goeunheuk, which manufactures and supplies raw red clay (hwangto) from a clean region of Boryeong, South Chungcheong Province. The site presents product specifications, applications and red clay path installation cases in a single flow, and includes STAYTOQ, our in-house AI chatbot, so inquiries are handled 24 hours a day.

  • Built a website organizing products and grain sizes (1.5, 2.5, 5mm) by use — from 20 and 25kg small bags to 500kg and 1-ton bulk bags and red clay–decomposed granite blends
  • Provided applications such as red clay paths, EM clay balls, water purification, fish farm application, plastering/ondol/hanok roof tiles and livestock barns, along with an installation gallery and a product brochure PDF
  • Installed STAYTOQ, our in-house AI chatbot, to answer inquiries about specifications, quantities and delivery 24 hours a day and connect to phone consultations
  • Designed mobile optimization together with search (SEO), directions and click-to-call paths
Visit 고은흙.com ↗See how we built it →
// 07 — products

Our products

We don't only build for clients. These are products we designed, built and run ourselves.

STAYTOQ

An AI service built for lodging operations · a 24-hour AI agent

STAYTOQ is our own AI chatbot SaaS, developed by SJ System and operated in live service. It answers inquiries for glamping sites, pensions and pool villas — including those that arrive in the middle of the night — and automatically responds across 4 channels at once: web, Naver TalkTalk, KakaoTalk and Instagram DM. It can also be added as a widget to websites and businesses outside the lodging industry.

Learn more →staytoq.com ↗

Rank Tracker

Beta

Naver Place rank tracking · keyword rank monitoring for shop owners

A service that automatically tracks where your shop ranks in Naver Place keyword searches and shows how it changes. It checks organic and ad rankings on a regular schedule, shows 31-day trend charts and sends an app push when ad rankings change. It also provides monthly search volume, Power Link advertisers, review counts and keyword suggestions by industry and area.

naverplaceranktracker.web.app ↗

Media Vault

In development

Media AI for video, photos and audio

A content management system (CMS) that brings video, photos and audio together in one place. AI search and scene analysis help you find the scene you need, and external partners receive copies carrying an invisible per-recipient watermark. Originals stay untouched; only purpose-built copies go out.

Learn more →
// 08 — admin-system

We build the operating system, too

STAYTOQ ADMIN

We didn't just build a chatbot. SJ System develops and operates the entire admin system owners use to actually run their properties.

Six areas — from AI responses to reservations, sales, website and task automation — are managed in a single admin. It is a multi-tenant architecture: data is separated per business, and the menus shown depend on each user's role.

6 areas28 menusLive in production

See what the chatbot handled and how much, and fix answers on the spot.

  • Dashboard
  • Inquiry & answer analytics
  • Basic information
  • Settings
  • Subscription billing

Bring all reservations into one place and manage check-in, check-out and cleaning just as they happen on site.

  • Room operations overview
  • Reservation status · Calendar
  • Check-in/out board · Check-in/out assignment
  • Cleaning schedule
  • Guest analytics · Messaging
  • Email import · Data consistency check

Take bookings and payments directly, through to settlement. Room inventory is kept in sync to prevent overbooking.

  • Sales overview
  • Room product management · Quick reservation management
  • Settlement (StayPay)
  • Coupons / Promotions
  • Product & option linking
  • Room inventory sync

Owners edit their property website themselves. No need to call a developer.

  • Site settings
  • Room information · Amenities
  • Images · Nearby attractions
  • Reviews · FAQ
  • Blog & notices · Legal pages

Schedule recurring promotional posts once and forget about them.

  • Instagram posting
  • Threads posting
  • Naver Blog
  • Channel connection settings

Compare with nearby properties as a reference when setting prices.

  • Competitor analysis
  • Quote calculator
staychat.kr/admin ↗More about STAYTOQ →

As this is a live production system, signing in requires an owner account.

// 09 — faq

Frequently asked questions

What kind of company is SJ System?

SJ System is an AI solutions development and implementation company that built STAYTOQ, an AI chatbot SaaS for lodging businesses, in-house and runs it as a live service. It was founded on March 10, 2023, and its CEO is Jiheung Jeong. We understand how a business works and build AI products and business systems. We run three businesses — industry AI services, custom AI & business systems, and AI transformation diagnosis & training — and the same team handles diagnosis, development, integration, rollout and ongoing operation.

What services does SJ System offer?

SJ System runs three businesses: Industry AI Services (STAYTOQ, Rank Tracker, Media Vault, Next industry); Custom AI & Business Systems (AI support, Internal knowledge search, Workflow automation, Web, apps and internal systems, Existing tool integration); AI Transformation Diagnosis & Training (Work analysis, Priority setting, Action plan, Hands-on training). AI Chat, AI Call, RAG, Agent and Automation are the technologies we use to deliver this work. The team that diagnoses builds and runs the result, and problems proven in the field become industry AI services (our own products).

What is STAYTOQ?

STAYTOQ is an AI chatbot SaaS for lodging businesses, developed and operated by SJ System. It answers guest inquiries automatically, 24/7, across 4 channels (Website widget, Naver TalkTalk, KakaoTalk, Instagram DM), and replies only with information the owner has confirmed. Pricing is KRW 29,000–99,000 / month (Based on business size, channels and inquiry volume · VAT excluded · No contract · 15-day free trial). Learn more at https://staytoq.com.

What does AI transformation diagnosis & training involve?

SJ System's AI transformation (AX) diagnosis and training looks at the work that takes the most time and the problems that keep recurring, decides what to solve first and in what order based on impact and feasibility, and trains staff to use AI in their actual work. When something needs to be built, the team that ran the diagnosis builds and runs it. Yangju JamJam Glamping & Caravan cut its guest-response time by 38.5 hours over the month of August 2026.

What projects has SJ System delivered?

Our flagship case is Yangju JamJam Glamping & Caravan. SJ System built everything — AI transformation diagnosis, the website, the STAYTOQ AI chatbot, booking and payment through our own StayPay, and the admin system — and it has handled 2,718 inquiries in total since May 2026. Other projects include the Goeunheuk website with STAYTOQ built in, and CallPop, a restaurant discovery platform (hybrid web app) in development for JudoSystems.

Who is the CEO of SJ System?

The CEO of SJ System is Jiheung Jeong. A full-stack and AI developer with 16 years of experience, he designed and built emart24's next-generation ERP and POS, the Korea Forest Service's ‘Supnadeul-e’, the Starbucks mobile upgrade, and an in-house AI help desk for a large enterprise. At SJ System he personally handles consultation, design, development and operations.

How do I contact SJ System?

Leave a message on the contact page of the SJ System website (sjsystem.ai.kr/contact) and it goes straight to the person in charge. You can also reach us by email (staytoq@sjsystem.ai.kr) or phone (0507-1339-7562), or ask the STAYTOQ chatbot in the bottom-right corner of the site first.