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Fjord Edu

Built a college-admissions academy's booking, payment, student workflow, and internal operations platform — handling over KRW 300 million in payments in a single day without downtime.

PersonalDuration 8 moContribution 100%2025-052025-12
Key Metric: First-come booking engine · ~2,000 concurrent bookings serialized
User Scale: Over KRW 300 million in payments in a single day · all opening traffic handled with zero incidents
Engineering Role
FullstackEnd-to-EndInfra
Fjord Edu project interface preview
Startup Build
Fjord Edu
AI
#Web#Frontend#Backend#Product

Overview

I built the booking, payment, student workflow, and internal operations platform for a college-admissions consulting academy from May through the end of 2025. It combines consultation booking, payment, pre-surveys, document uploads, and administrator assignment, with a FOR UPDATE SKIP LOCKED + Optimistic Locking booking engine and Toss PG handling over KRW 300 million in payments in a single day without downtime.

My Work

  • Owned the full lifecycle across planning · UX · design · full-stack development · deployment · operations
  • Serialized ~2,000 concurrent bookings with FOR UPDATE SKIP LOCKED + Optimistic Locking + RPC
  • Integrated Toss PG confirm, recovery, whitelist revocation, and 10-minute hold expiry
  • Built one Google · Kakao OAuth callback for identity linking and inactive-account blocking
  • Applied Supabase RLS, security definer hardening, and 100+ SQL migrations
  • Built admin-editable cms_pages, block visibility, SEO meta, banners, menus, and popups

Features

  • First-come slot lookup/booking/payment flow (handling ~2,000 concurrent users)
  • Toss Payments approval/refund + payment recovery / automatic whitelist revocation
  • Google · Kakao · Email login + account linking on My Page
  • Pre-survey questionnaire + administrator CSV export
  • Document submission upload (PDF/JPG/PNG/HWP/ZIP · 100MB)
  • Page-builder CMS for home, booking, notices, and regular-admission pages

Highlights

  • Built May–Dec 2025 · maintenance and operations since
  • First-come booking engine (FOR UPDATE SKIP LOCKED + Optimistic Locking + RPC)
  • Handled all opening traffic · over KRW 300 million in payments in a single day with zero incidents
  • Toss Payments PG approval · refund · pg_cron 10-minute hold auto-expiry
  • CMS — page builder · block visibility · banners · menus · popups · per-page SEO meta

Timeline

2025-052025-12
Role: Planning · design · full-stack development · deployment · maintenance operations
Contribution: 100%
Collaboration: Personal

Tech Stack

</>Next.js · Supabase RLS · Toss PG · first-come booking engine

Next.js 16React 19TypeScriptTailwind CSSSupabasePostgreSQL (RLS · FOR UPDATE SKIP LOCKED · pg_cron)Toss PaymentsRechartsPlotly.jsTiptapVercel

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