SJ System
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About

SJ System is an AI development company that built STAYTOQ in-house — an AI chatbot SaaS for lodging businesses, now running as a live service at customer properties.

The team that builds its own AI also builds your apps and websites. From Android and iOS apps (CallPop) to corporate websites and custom systems, we handle planning, development and operations as a single team.

CEO
Jiheung Jeong →
Founded
March 10, 2023

History

The path we've taken since our founding. Each milestone is based on actual development and launch records.

  1. SJ System founded

    Drawing on 16 years of building core systems for large enterprises, we opened our doors with one goal: to help small companies work like big teams.

  2. Full-scale AI development begins

    We built AI design and operations expertise by developing LLM-based services as our own projects. This is when we went beyond plugging in someone else's API and gained experience building and running AI ourselves.

  3. STAYTOQ admin system developed

    We developed an admin system that handles the full scope of property operations — bookings, check-in and check-out, cleaning schedules, settlement and the website — from a single screen. Its multi-tenant architecture, with data separated by business and menus that change by role, later became the foundation of STAYTOQ.

  4. AI chatbot ‘STAYTOQ’ launched

    We added an AI chatbot built for lodging businesses on top of the admin system and rolled it out to our first official partner, Yangju JamJam Glamping & Caravan. That same month we added Naver TalkTalk integration, pricing plans and a free trial, and began live service.

  5. StayPay payments built · CallPop app development begins

    We developed StayPay, which handles bookings, payments and refunds directly, and completed our Mail-order business registration. We also began developing CallPop, a restaurant discovery platform, as a hybrid web app for JudoSystems.

  6. AI team operating model established

    We set up an in-house operating model in which assistant, developer, marketing and accounting AI do real work and the CEO approves it. We applied the idea of one person doing the work of a whole team to ourselves first.

  7. Live service results validated

    STAYTOQ automatically handled 770 inquiries in one month, with a 96.4% response rate and 38.5 hours of response time saved. In the same period we built the Goeunheuk website, expanding our website development business.

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.

The hours lost answering inquiries at dawn, copying bookings from one place to another, giving the same instructions a hundred times — winning that time back is what every service we build ultimately exists for. We believe the time saved should go back into better lives and more meaningful work.

Vision

A world where small companies work like big teams.

We want to end the era when growing meant hiring more people.

A guesthouse with a handful of staff, a shop run by one person, a solo business — all working with AI teammates as a matter of course. SJ System works to lower that barrier.

Our principles

We prove it in hours

We measure results not by how many features we ship, but by how many hours a month we give back. At one property, STAYTOQ cut guest-response time by 38.5 hours a month.

We use it ourselves first

We run assistant, developer, marketing and accounting AI in-house first. We only apply approaches to clients that we use every day and have seen work.

We don't guess

Without evidence, we don't answer. A plausible wrong answer doesn't save time — it costs more time to clean up. That's why STAYTOQ hands questions it can't answer over to a phone call.

The people who build it run it

We don't deliver and walk away. We built STAYTOQ ourselves and run it as a live service for our clients, and the websites we build come with the chatbot on board so they keep capturing inquiries.

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.

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.