When a listing disappears, assume it sold: how a small Korean app beat official sale prices by 30 days

Burupang does one thing: four times a day it scans listings across about 6,000 apartment complexes in Korea, and any listing that disappears gets marked "likely sold", before the Ministry of Land publishes actual sale prices. It's free, needs no signup, has no in-app purchases, and has only 3,233 Android installs in total. What's worth noticing isn't its size but two things: it turned an official data lag into a product, and it built up users with a website and automated posts before launching an app.

A blogger tracking listings in Excel

Late August 2026, Naver blogger 99sslee published a post titled 《네이버 부동산에서 사라진 매물은 어디로?》 (Where did the listings vanish from Naver Real Estate?). She wrote that last June, when her sister was switching homes, "the asking price jumped tens of millions of won in a single day, and the place we liked just disappeared." Since then she has logged the listings for the apartment complex she invested in two or three times a month, in Excel.

"When there are few listings it's fine. Once there are a bit more, you have to match rows against last time's table one by one: 'Listings are down... but which one went missing?'"

Naver Real Estate only shows listings that are currently up. Once a unit is delisted, you can't see what it was asking or whether it sold or the owner pulled it. The first site she recommended was Burupang: "It's pretty close to my Excel method of finding 'there last time, gone this time'. Feels familiar."

In October 23, on Korea's biggest apartment forum 호갱노노, someone posted in a Dongtan complex thread: "Burupang? It says the two 84-pyeong units, 800M and 760M, disappeared. Is the sold guess accurate?" A reply said those were detected as gone because the price had changed (4 likes). Users were already discussing their complex's market using its signals. Whether they're accurate is a separate question.

What it is

Open the burupang.com homepage and the screen is all cards: "11-06 gone, 1.6B 50M, Bangpo-dong, Seocho-gu, Seoul, 102 building, mid floor/35, south-facing, 110/84㎡ (33 pyeong), confirmed 10-14". Some cards have an extra line below: "Last actual sale 6.2B 80M (09-23), 12.4% change".

• Signal: "gone" tracked at the individual listing level (building, floor, orientation, area, asking price), updated four times a day (that page states 11-06, 06:52, 11:55, 17:09, 22:02). It covers sales, jeonse and monthly rent. On Nov 6 alone, 1,371 units disappeared in total (burupang.com, 11-06 evening).
• Comparison: how much the last recorded sale price for that unit type moved up or down.
• Alerts: star a complex and get a push when a new listing disappears there.
• Honesty: the page says "gone" can also mean a delisting or expiry, and that it's an estimate, not a confirmed sale.
• Coverage: the official site says it covers 6,196 complexes nationwide.
• Launch: the website has existed for at least 2026 years since June; the iOS app went up in Sep 22 and the Android app followed around late Sep 25 (both per its own Instagram launch posts). The iOS seller is With H&K Corp.; the team's background is unclear.

Why people need it: official sale prices lag by a month

Korea's actual apartment transaction prices: the law only requires reporting within 30 days of signing, so the market can move this month while the numbers only show up next month. In 2026 the Seoul metro area has land transaction permit zones and loan restrictions, so deals were already few and every single one moves the read. The similar product 급매캐치 tracks its own data and found reporting in permit zones lags closing by about 35 days on average.

Something filled this gap before: the veteran 아실 (2.75M Android installs) had a "매물증감" feature showing how listing counts changed by area and complex, but it didn't tell you which unit. In 2025 Aug 8, 아실 also announced it was shutting that service down because it "couldn't collect the raw data" (파이낸셜뉴스). Big platforms like 호갱노노 and KB부동산 cover actual sale prices and current listings, but nobody was doing "which unit disappeared."

The demand was already there, and people were doing it by hand. The tool was missing, and Burupang automated that blogger's Excel sheet.

Where users come from: thousands of auto-generated pages, plus dozens of templated posts a day

It appears to have spent almost nothing on paid acquisition (no evidence of ads found), and its users come from three layers:

1. Programmatic SEO. The site auto-generates pages by complex (/complexes, over six thousand pages), by city and district (/regions, with titles like "Gyeonggi Gunpo-si apartment complexes 40 — sale signals · actual sale prices"), and by date (/dates, one page per day). Anyone who searches their own complex's name has a chance of landing on it.
2. Daily templated social posts. The Threads account @boo.lupin0342 has posted about 3,300 times, with 1.4K followers, and every post follows the same format: "As of 20 o'clock today, N units disappeared from major apartments in <area>" + the first 5 units + "Search 'Burupang' on the App Store / Google Play." Instagram (182 posts, 44 followers), YouTube Shorts (170 videos, 8 subscribers) and Naver blog (265 posts) get the same content. Engagement on these accounts is low, one or two likes per Instagram post. Their job is to feed search, not to build a following.
3. Mentioned in niche circles. A Naver blogger's recommendation (whether paid is unverified) and posts in the 호갱노노 complex discussion threads.

The app came later. It drove traffic to the website on Instagram starting in June, and in late September it posted the app launch, with release notes saying "your old watchlist is still on the browser at burupang.com", which means the website already had a base of older users. The app's role is push alerts, to bring people back every day.

Scale

Google Play data, 11-06. Over the last 7 days, +726, around a hundred a day. From Oct 29 to Nov 6 it was on the Korea House & Home free chart every day, ranking #30–37. That category has a low bar: a hundred new installs a day gets you into the top 40. The iOS Korea store has only 1 ratings, and Play has no ratings or reviews yet. It's small, but steady, and almost all organic.

Who it's competing with

Burupang's only difference is that this is its sole feature, it covers the whole country, needs no login, and sends alerts per complex. The differentiation is real, and it's why people talk about it, but it's shallow. The biggest risk isn't the competitors, it's the data: if it scrapes Naver's listings, 아실's history shows that pipe can be shut off at any time.

It charges nothing right now. Whether it will rely on subscriptions, agency deals or ads later is unclear.

If it were you

C: you can learn from it, but copying it isn't worth much. Building another Burupang in Korea means entering a market where two players already run it, it's free, has thousands of users, and its data is scraped from others. What's valuable is its two tactics, which you can take elsewhere.

• Who it suits: people who understand a particular country's property market (or another field where official data lags), who can write scrapers and programmatic pages, and who are 1–2 fluent in that market's language, able to write posts that sound like a local wrote them.
• Who it doesn't suit: anyone who wants to go head-to-head with 급매캐치 or 아실 in Korea, anyone who needs money quickly (this kind of tool's users are retail buyers checking prices, and their willingness to pay is unclear), and anyone unwilling to take on the compliance risk of the data source.
• How to do it: find a market where official sale or statistics data has a clear lag, but there's an earlier public proxy signal. In property, you could look at Taiwan (its actual-price registration also has a reporting lag), Japan, or Southeast Asian listing sites (inferred, you'd need to verify local data and platform terms yourself). Launch the website first: auto-generate pages by complex, area and date, where every page has specific listings and prices, be honest that it's an estimate, and only build push alerts once people come back daily.
• How to get users: copy its approach. Where locals look at property (Threads, RedNote, PTT, forums), post a templated update every day, "Today X district, N units gone + the first 5 + how to find me", which costs almost nothing. Then go to the biggest local complex forums and property bloggers and get "tracking disappeared listings" talked about organically.
• Before when?: No hard deadline. This window depends on how tight regulation is and how cold deals are. If rules loosen and deal volume rises, the time advantage stops being worth much.
• What would mean I got it wrong: ① 부루팡 or 급매캐치 starts charging, and App ratings and installs keep climbing. That would mean people will pay for this signal, so the grade should go up. ② 호갱노노 or 아실 launches single-unit disappearance tracking. That would mean a big platform absorbed the feature and leaves no room for small teams. ③ 부루팡's data suddenly stops updating or coverage of complexes drops sharply. That would mean the data source got cut, and this path has to be re-evaluated in any market that relies on scraping third-party listings.