Yonsei Mileage Viewer

Overview

A web app for instantly looking up Yonsei University mileage course-registration results by course-section number. I reverse-engineered the school's internal results endpoint to make responses faster than the official page, reaching 60,000+ daily lookups and 4,000 concurrent users over 30 minutes in the first season.

My Work

• ▸Analyzed the school's internal results-lookup endpoint + a direct call pipeline
• ▸Used normalization, caching, and indexing for faster responses than the official system
• ▸Handled traffic surges (4,000 concurrent users over 30 minutes)
• ▸UX redesign — far faster navigation than the school's official site
• ▸Two iterations: first-season viewer (2024-02 ~ 2025-02) + follow-up helper (2025-02 ~ 2026-02)

Features

• Enter course-section number → instant lookup of past mileage results
• Fast UI searchable instantly during the registration season
• A cache/normalization layer faster than the school's official responses

Highlights

• Reverse-engineered Yonsei's internal mileage results endpoint → backend hijacking
• Perceived speed advantage over the official school site → went viral during registration season
• 60,000+ daily lookups · 4,000 concurrent users over 30 minutes
• Operated two seasons: first as viewer, then as helper

Timeline

Tech Stack

</>Next.js · Vercel · backend reverse-engineering · high traffic

Links