Building a Rental Aggregator When Daft.ie Already Exists
When people find out I'm building a rental search platform for Dublin, the first question is usually some version of: "But why? Daft is already there."
It's a fair question. Daft.ie has dominant market share, brand recognition, a large team, and a listings database built over two decades. If I'm building something in the same space, I need a reason that goes beyond "I'll make it better." Better at what? By whose measure? And what's stopping Daft from just adding that feature?
Here's how I actually thought about it, and what the technical implications turned out to be.
What Daft does that I can't replicate
Before anything else: what Daft has that I don't have is supply-side lock-in. Landlords and letting agencies list on Daft because that's where renters look. Renters look on Daft because that's where landlords list. This is a genuine two-sided network effect that took years to build and can't be engineered around.
I'm not going to out-list Daft. My product doesn't have a listings CMS, a landlord login, or a monetized ad product. I don't want those things. That's not the game I'm playing.
The gap that aggregation addresses
Daft has a lot of listings. It doesn't have all of them.
The Dublin rental market has listings spread across Rent.ie, MyHome, smaller agency portals, property management company websites, and secondary platforms. Some letting agencies and landlords don't post to Daft at all. Others post there but also post to their own site with photos or descriptions that differ slightly.
When I was looking for a flat myself, I was checking six separate sites manually. That's the gap: not better listings, but a unified view of the listings that already exist.
The question then becomes: can I build a technical product that's genuinely better at aggregation than a user doing manual searches? And is that worth doing?
The aggregation architecture
The core is a crawler that runs on a schedule, pulling listing data from Daft.ie and Rent.ie. The challenges that weren't obvious until I was in it:
Source heterogeneity. Each source has its own structure. Daft has a clean API-like interface. Small letting agency sites are often hand-built with inconsistent HTML. Property management company sites sometimes generate listings dynamically in JavaScript, which complicates standard scraping. You end up with a per-source adapter layer that handles idiosyncrasies, feeding a shared normalization layer.
Deduplication. The same apartment often appears on three or four sources simultaneously. Without deduplication, a user sees the same property four times and thinks the market has more supply than it does. Deduplication based on address alone doesn't work reliably because addresses aren't formatted consistently. I use a combination of address fuzzy matching, price comparison, and image fingerprinting (when photos are available) to group duplicates. It's not perfect. False positives (merging two distinct listings) are worse than false negatives (showing a duplicate), so I tune conservative.
Change detection. Knowing that a listing is new requires knowing what was there before. Knowing that a listing is gone requires distinguishing "temporarily de-listed" from "taken." I keep a snapshot of each crawl and diff it against the previous one. Listings that are absent for two consecutive crawl cycles get marked as likely gone rather than immediately. This reduces false "this listing was taken" alerts.
Price normalization. Some sources list weekly prices, some monthly. Some include bills, some don't. All prices in the system get converted to monthly EUR before storage. This sounds trivial and took an embarrassing amount of time to get right across all sources.
Why not just build on top of Daft's data?
The obvious question. Daft has terms of service that prohibit scraping. More practically, building your entire product on one source you don't control creates a single point of failure that a cease-and-desist, a terms change, or a UI redesign can eliminate overnight.
The multi-source architecture is a risk hedge as much as a product feature. Any single source can break or become unavailable. Crawlers fall behind when sites update their structure. Source diversity means no individual source going offline kills the product.
Where this actually competes with Daft
It doesn't compete on listing volume for properties that are Daft-exclusive. It competes on:
Cross-source coverage. If a letting agency posts a property on their own site and nowhere else, my system finds it. Daft doesn't.
Search. Daft's search is filter-based: price range, beds, area from a dropdown. My search accepts natural language and handles the translation to structured filters. "2-bed near Ranelagh Luas, under 1900, pet-friendly" resolves to a structured query without the user having to manually set each filter.
Alerts. My alerts cover Daft.ie and Rent.ie simultaneously. A user doesn't have to set up and maintain separate alert logic on both portals.
Features Daft hasn't prioritized. AI lease review, application tracking, email composer. Features that are useful for the renter's workflow beyond just finding listings.
None of these make me "better than Daft" on Daft's terms. On the specific things I'm competing on, the product is genuinely different.
The strategic frame
The word "competing" is actually a bit wrong here. My product wraps publicly available listing data from Daft.ie and Rent.ie into a faster search and alert workflow. Daft is a source of inventory, not just a competitor. The relationship is asymmetric: they don't know or care I exist; I depend on continued public availability.
This creates a dependency risk I think about seriously. The mitigation is source diversity, features that add value beyond the listings themselves, and building enough user value that switching away from Daft's data specifically wouldn't kill the product.
I wrote a longer breakdown of the full comparison between portals and aggregators at https://homescout.io/guide/better-than-daft-dublin-rentals if you want the user-facing version of this.
Caspar Bannink. Founder of HomeScout.io. Building AI-powered rental search for Dublin.