Scraping Japan's Largest Real Estate Site with a Chrome Extension: Building an Automated Property Scoring Engine

If you've ever apartment-hunted in Japan, you know the drill. You open SUUMO -- the country's dominant real estate portal, think Zillow but with near-monopoly status -- and you're immediately staring at dozens of property listings. Each card shows rent, area, station distance, building age. But the numbers that actually matter for making a decision? Those aren't there. You have to calculate them yourself, mentally, for every single listing. Price per square meter. Total move-in cost (which in Japan includes a dizzying mix of deposits, "key money," brokerage fees, insurance, and lock replacement charges). Two-year total cost of living. Whether the asking price is reasonable compared to the neighborhood average. I got tired of doing this math on paper, so I built Bukken Scouter -- a pair of Chrome extensions that inject real-time financial analysis directly into SUUMO's listing pages. One for purchases (condos and houses), one for rentals. Both are built on Manifest V3, React, TypeScript