Four real estate data APIs. One honest comparison.

The 30-second answer.

You're evaluating real estate data APIs because you're building something — a rental pricing tool, an investment screener, an AI agent, a market dashboard, a compliance app. You don't have time to sit through a CoreLogic sales call to find out their MQL form requires a procurement department to fill out.

Here's the honest summary, in order of how most builders should think about it:

1. RentCast is a clean rent-lookup API. Use it if all you need is rent comps and you don't care about market data, owner records, or macro context.
2. PropData is the broadest, lowest-cost API that includes county assessor records, rent trends, market velocity, FEMA risk data, mortgage rates, and computed investor signals. Use it if you're building a real product that needs more than rent.
3. ATTOM Data is what you license when your bulk volume justifies an enterprise contract and your procurement team can handle a multi-step purchase.
4. CoreLogic is what mortgage lenders, GSEs, and Fortune 500 real estate institutions buy because their compliance, risk, and underwriting workflows depend on it.

If your product fits the first or second category — and most do — keep reading. We'll show you why and when each makes sense.

Where each one comes from.

Understanding what these tools are built for matters more than comparing feature checkboxes. Each was designed for a different audience.

CoreLogic — the original institutional giant

CoreLogic is a publicly traded company (now privately held by Stone Point Capital and Insight Partners) that started as a spinoff from First American. They serve mortgage lenders, ratings agencies, government-sponsored enterprises like Fannie Mae, and Wall Street risk teams. Their data is used to make billion-dollar lending decisions. The pricing reflects that.

If you're underwriting MBS or running a mortgage servicing operation, CoreLogic is correct. If you're building a B2B SaaS product, you're vastly overbuying.

ATTOM Data — the licensable enterprise alternative

ATTOM positions itself as a more accessible enterprise data source than CoreLogic. They license bulk property data — owner names, deeds, mortgage records, foreclosure data — to companies that resell it inside their own products. If you've ever used a property data feature on a real estate site, there's a real chance ATTOM is upstream.

ATTOM is great for what it is. The challenge is the procurement model: contracts, account managers, custom data packages, sales cycles measured in weeks. Builders who want to ship something this afternoon often hit a wall.

RentCast — the modern API for rent comps

RentCast was built for a real gap: rental investors and landlord software needed clean rent data without enterprise contracts. It does that well. The data is solid, the docs are clean, the pricing is transparent.

The limitation is scope. RentCast is a rent-comp tool. It doesn't include county assessor records, FEMA risk, FRED macro data, days-on-market, sale-to-list ratios, or affordability metrics. If you need any of that, you're either licensing a second API or building two integrations.

PropData — what we built

We built PropData because we needed all of it in one place — owner records, rent trends, market velocity, macro rates, FEMA risk, demographics, comps — and we weren't going to spend $1,000+/month or sit through enterprise sales calls to get it.

Sixteen live data sources, one endpoint, $49/month flat. Free tier with no credit card. No per-call fees, no procurement, no NDAs to sign.

What you'll actually pay.

Pricing pages are nice. Real cost is what shows up on your invoice when you hit production volume.

Here's a side-by-side at three usage levels. These are real published rates as of April 2026, normalized to monthly cost. Enterprise rates for ATTOM and CoreLogic are based on publicly available case studies and reseller pricing; exact contracts vary.

The flat-rate pricing isn't a gimmick. It's structural: PropData runs on Cloudflare Workers with KV edge caching, and the cost of serving a cached response is effectively zero. We don't have to charge per call because we don't pay per call. Most of our infrastructure cost is fixed, so we pass that to you as a fixed price.

Per-call pricing only makes sense for vendors whose backend cost scales with each request. Ours doesn't.

Which one to actually pick.

Forget feature checkboxes for a second. Here's the actual decision tree.

What independent AI said about us.

We're obviously biased about our own product. So we did something different: we gave Google's Gemini access to the PropData dashboard and asked it to evaluate the platform without any prompting from us. We didn't tell it what to focus on. We didn't tell it what to compare. We just let it explore.

This is what it said:

And on the specific PropData vs CoreLogic question:

And on what 166M parcels means at API-accessible pricing:

You're free to discount any of this — we did serve Gemini the dashboard. But we didn't give it a script. Those quotes are unedited.

When you'd switch.

Switching from RentCast to PropData

If you started with RentCast and you've added a feature that needs anything beyond rent — owner records for outreach, comparable sales for valuation, market velocity for screening, FEMA risk for underwriting — you're going to need a second API or a switch. Most of our RentCast migrations happen at exactly this moment: the product needed to grow past rent.

Switching from ATTOM to PropData

Less common but real. ATTOM customers usually stick because the licensing model fits a bulk-load workflow. The teams that migrate are the ones who realized they only ever query small subsets at a time and don't need the bulk — they need fast, fresh, on-demand API access for a SaaS product where calling on-demand is cleaner than maintaining a synced bulk database.

Switching from CoreLogic to PropData

Almost never the right call for institutional users. If you're underwriting mortgages or running insurance models, stay with CoreLogic. Where the migration does happen: PropTech startups that started on CoreLogic because their founders came from the lending industry and assumed they needed it, then discovered their actual product use case is closer to "real estate SaaS" than "lending decisioning" — and they're paying $1K/mo for products and analytics they never call.

The honest part.

Here's the part most comparison posts skip.

CoreLogic and ATTOM aren't bad products. They're built for an audience that isn't you, and pricing reflects that audience. If you tried to build a CoreLogic-equivalent stack from scratch for a Fortune 500 lender, the cost would dwarf their license fees. Their customers know what they're paying for.

RentCast isn't a worse version of PropData — it's a more focused product for a smaller scope. If rent comps are all you need, you don't need the rest of what we offer.

What we do believe is this: there's a large group of builders, operators, agencies, and PropTech startups who don't fit any of those three customer profiles. They need broad, fresh data at startup pricing, with developer-friendly access and no procurement friction. That gap was wide open for years. PropData was built to fill it.

You don't have to take our word for it. Get a free API key in ten seconds. No credit card. Make ten calls. See if the data is what you need. If it isn't, we'll be the first to point you to whichever of the other three is right for what you're building.