What makes a portal fail
Property portals rarely fail for lack of listings. They fail because the same flat appears six times at four prices, because half the entries were sold months ago, and because the search returns everything and therefore nothing. Users learn this within two visits and stop coming back, at which point the agents stop uploading, and the decline becomes self-reinforcing. The commercial layer has its own problem: agents will not pay for promotion until they can see what it returns.
What we build for a property portal
First, feed ingestion with duplicate detection, so one property is one listing no matter how many agents post it. Second, moderation and automatic expiry, which is what keeps the catalogue believable at scale. Third, search built for how people look: map, district, commute, payment — with performance that survives a large index. Fourth, agent accounts with transparent statistics and paid promotion, so the monetisation is something agents can justify.