How to Build a Real Estate Listings App with AI
Contents
Last updated: August 2026.
MLS data access, display rules, and fair housing compliance determine whether a real estate app actually works, not the screens, the map view, or the saved-search feature that show up in a demo. None of that shows up in a pitch deck either, which is exactly why it catches first-time builders off guard. The good news is that the app-building side of this, the part that used to cost the most, is no longer where the money has to go.
The MLS problem, and why RETS is already dead
Legacy RETS feeds were shut off for good at the end of 2024. RESO Web API 2.0 is now the standard at more than three-quarters of MLS providers, and any new build should be designed around it rather than the older protocol. Not all MLS boards are equal, though: RESO certifies them at platinum, gold, or silver levels, and a lower certification level usually means older field coverage and more manual normalization work on your end. Check your target board's certification level during scoping, before assuming a clean, consistent data feed.
What changed with the 2024 NAR settlement
The settlement that took effect in August 2024 changed how cooperation and compensation fields are handled in MLS feeds and moved buyer-broker agreements to a written, signed model. New builds need to handle the updated schema by default rather than assuming an offer-of-compensation field will simply appear the way it used to. Treating MLS data as a compliance-aware, normalized layer rather than a feed you display directly is what keeps a build from breaking every time a board updates its schema.
IDX and VOW aren't the same display rules
IDX rules govern what listing data can be shown publicly, to any visitor. VOW (Virtual Office Website) rules govern a broader subset of data available only to registered, authenticated users. These are legally distinct, not just two settings on the same feature, and confusing them is a common way new real estate apps end up showing data they aren't licensed to display publicly.
Fair housing rules apply to features that feel purely technical
A natural-language search feature or an AI-driven recommendation engine can inadvertently enable discriminatory filtering if fair housing rules aren't built into the logic from the start, not reviewed as an afterthought. The same caution applies to computer-vision photo tagging and any personalization layer, the feature needs to save genuine time without becoming a filtering mechanism that steers users along protected characteristics.
Build versus buy, and where Huxly actually fits
Established platforms like Matrix, Flexmls, and Paragon already cover a standard agent or brokerage website well, and for that use case, buying usually wins on both speed and cost. Custom development pays off when your product needs workflows, data combinations, or differentiation those platforms don't support.
If you're building custom, split the work honestly into two pieces. The MLS integration and the compliance-aware data layer, IDX/VOW rules, fair housing logic, multi-board normalization, are specialized work no tool automates away, that part needs real expertise regardless of what builds the app around it. The native mobile app itself, screens, navigation, search UI, saved listings, is the part Huxly generates directly from a prompt in Expo, Flutter, or SwiftUI, with a live simulator and one-click backend connections to Supabase, Firebase, or Neon for the app's own data (favorites, saved searches, user accounts), for a flat $25 or $99 a month rather than agency day rates. That doesn't replace the MLS and compliance work described above, but it means the app-shell portion of the budget below shrinks substantially instead of scaling with the same hourly rate as the specialized data work.
Design for more than one MLS from day one
Single-MLS architectures rarely stay single-MLS for long, and a normalization layer that handles multiple boards' data structures is far cheaper to build correctly at the start than to retrofit once a second board's feed is already live.
What this costs to build
A custom-development agency handling both the app and the MLS integration typically quotes $25,000 to $75,000 for a focused MVP over 6 to 8 months, and $75,000 to $150,000 or more for a multi-platform build with advanced data handling, virtual tours, e-signing, and back-office features. Most of that figure is the MLS integration, compliance layer, and agency overhead, not the app-building step itself. Prompting the native app through Huxly at $25 or $99 a month removes a real chunk of that cost, while the MLS/compliance work still has to happen through a developer or a specialized MLS integration service either way. For the broader cost picture across app categories, see our breakdown of what it costs to build a mobile app in 2026.
FAQ
Is RETS still used for MLS data feeds?
No, legacy RETS feeds were shut off at the end of 2024. RESO Web API 2.0 is the current standard across most MLS boards, and new builds should be designed around it.
What's the difference between IDX and VOW data access?
IDX governs what listing data can be shown to any public visitor. VOW governs a broader set of data available only to registered, authenticated users. They're legally distinct rule sets, not two versions of the same feature.
How did the 2024 NAR settlement affect app development?
It changed how cooperation and compensation fields are structured in MLS feeds and moved buyer-broker agreements to a written, signed model. New builds need to handle the updated schema rather than assuming older field structures.
Do fair housing rules really apply to app features like AI search?
Yes. Natural-language search, recommendation engines, and photo-tagging features can all inadvertently enable discriminatory filtering if fair housing considerations aren't built into the underlying logic from the start.
Should I build a custom real estate app or use an existing platform like Flexmls?
For a standard agent or brokerage website, an established platform usually wins on speed and cost. Custom development makes sense when you need workflows or data combinations those platforms don't support.
Can Huxly handle the MLS integration itself?
No, and it's worth being direct about that. MLS integration and fair housing compliance are specialized work regardless of which tool builds the app around them. What Huxly handles is the native app itself, generated from a prompt, so that specialized work isn't also paying agency rates for standard screens and navigation.
How much does a real estate listings app cost to build?
An agency handling everything typically quotes $25,000 to $75,000 for a focused MVP, up to $150,000 or more for a multi-platform build. Building the app itself through Huxly ($25 or $99 a month) cuts a real portion of that, while the MLS and compliance work still needs a developer or specialized integration service regardless.
Why does MLS certification level matter if I'm just displaying listings?
A board's RESO certification level (platinum, gold, or silver) affects how complete and consistent its data fields are. Lower-certified boards often mean more manual normalization work to get clean, reliable data into your app.
