Building a rental aggregator for Dublin means pulling data from a fragmented market: one dominant portal, a handful of mid-tier sites, dozens of letting agency websites, property management company portals, and a long tail of small sources. Here's how the system is structured and where the interesting problems are.

Why existing portals aren't enough

The standard answer for finding Dublin rentals is Daft.ie. It has good coverage and solid search. The problem is that coverage isn't complete. Letting agencies list exclusively on their own websites. Some landlords use smaller portals. A non-trivial share of listings never hits Daft at all.

If you're only searching Daft, you're seeing maybe 60-70% of what's available. For a renter in a tight market, that gap matters.

An aggregator's value proposition is simple: search everything, show results in one place.…