License & Deployment Mix: 10 tools – 0 OSS, 10 SaaS. (OSS and SaaS counts can overlap when an open-source tool also offers a vendor-hosted edition.)
Note: Data-primary – MLS / county records.
What Is Property Data?
Property data is a data-primary category. Unlike most tool evaluations where the value is in the software, property data services derive their value from proprietary datasets – massive, continuously updated databases of real estate records, property valuations, ownership history, MLS listings, tax assessments, and title records. The software (portals, APIs, analytics dashboards) is simply the front end for accessing this data.
OSS is not viable here. Open-source software cannot replicate the proprietary data pipelines that aggregate MLS feeds from 600+ local boards, scrape and normalize county recorder records from 3,100+ US counties, or build automated valuation models trained on decades of transaction history. The product IS the data, not the code that serves it.
Property data services are consumed through:
- API-based property lookups – real-time queries by address, parcel ID, or APN returning property attributes, valuations, and ownership
- Bulk data feeds – scheduled or streaming delivery of property records, transactions, and listing data for warehousing and analytics
- Automated Valuation Models (AVMs) – algorithmic property valuations used for lending, insurance, and investment decisions
- Analytics platforms – web portals for market research, comps analysis, risk assessment, and portfolio management
The information on these pages was researched by a combination of human review and large language models. To suggest an addition or correction, please contact us. Prepared by Rhodium Systems Inc., author of the ResorsIT platform — a unified IT operations management platform for IT teams and MSPs that integrates a curated suite of open-source, commercial, and SaaS applications into a single system with shared identity, single sign-on, access control, and a common audit trail. Use this catalogue only as a starting point for your own research, and review any tool carefully against your own requirements before relying on it. Catalogue data version 2026.197.
Comparison
Property data services are data-primary products – the value is the proprietary dataset, not the software. All tools in this category are proprietary commercial services with no self-hosted or open-source alternatives. They are integration targets for real estate, mortgage lending, insurance, and PropTech.
SAML is the most common SSO protocol for enterprise data portals, with API access typically using OAuth 2.0 or API keys.
SSO / OIDC Comparison
SAML is the dominant SSO protocol for property data enterprise portals.
| Tool | OIDC | SAML | API Auth | Authentik Notes |
|---|---|---|---|---|
| CoreLogic | No | Yes | OAuth 2.0 / API key | SAML via Authentik SAML provider |
| ATTOM | No | No | API key | No portal SSO; API key only |
| Zillow | No | No | API key (ZWSID) | No enterprise SSO; consumer OAuth only |
| CoStar | No | Yes | API key / OAuth 2.0 | SAML via Authentik SAML provider |
| Redfin | No | No | No public API | No enterprise SSO; consumer login only |
| Reonomy | Yes* | Yes | API key / OAuth 2.0 | OIDC or SAML via Authentik |
| Black Knight | No | Yes | OAuth 2.0 / mTLS | SAML via Authentik SAML provider |
| First American | No | Yes | OAuth 2.0 / API key | SAML via Authentik SAML provider |
| HouseCanary | No | No | API key (Bearer) | No portal SSO; API key auth |
| Estated | No | No | API key | No enterprise SSO; API key only |
* = available on specific products or editions
Best SSO support: CoreLogic, CoStar, Black Knight, First American (enterprise SAML portals); Reonomy (OIDC + SAML)
No SSO: ATTOM, Zillow, Redfin, HouseCanary, Estated (API-first platforms with no enterprise portal SSO)
API Comparison
| Tool | API Type | Auth | Real-Time | Batch | Pricing Model |
|---|---|---|---|---|---|
| CoreLogic | REST | OAuth 2.0 | Yes | Yes | Per-query + subscription |
| ATTOM | REST | API key | Yes | Yes | Per-query tiers |
| Zillow | REST | API key | Yes | No | Free tier + paid |
| CoStar | REST | OAuth 2.0 | Yes | Yes | Enterprise subscription |
| Redfin | None (public) | N/A | N/A | N/A | N/A |
| Reonomy | REST | OAuth 2.0 | Yes | Yes | Enterprise subscription |
| Black Knight | REST / SOAP | OAuth 2.0 | Yes | Yes | Enterprise subscription |
| First American | REST | OAuth 2.0 | Yes | Yes | Per-query + subscription |
| HouseCanary | REST | Bearer token | Yes | Yes | Per-query tiers |
| Estated | REST | API key | Yes | Yes | Per-query tiers |
Property Data Coverage
| Tool | AVM | MLS Data | Tax/Assessor | Deed/Title | Foreclosure | Flood/Hazard | Segment |
|---|---|---|---|---|---|---|---|
| CoreLogic | Yes | Yes (600+ MLSs) | Yes (3,100 counties) | Yes | Yes | Yes | Residential + Commercial |
| ATTOM | Yes | Limited | Yes (3,100 counties) | Yes | Yes | Yes | Residential |
| Zillow | Yes (Zestimate) | Yes (own feeds) | Limited | No | Limited | No | Residential (consumer) |
| CoStar | Yes (commercial) | No | Yes | Yes | No | Limited | Commercial |
| Redfin | Yes (Redfin Est.) | Yes (own feeds) | Limited | No | No | No | Residential (consumer) |
| Reonomy | No | No | Yes | Yes | No | No | Commercial |
| Black Knight | Yes | Yes | Yes (3,100 counties) | Yes | Yes | Yes | Residential + Mortgage |
| First American | Yes | Limited | Yes (3,100 counties) | Yes | Yes | Yes | Residential + Title |
| HouseCanary | Yes | Yes (via partners) | Yes | Limited | Yes | Yes | Residential |
| Estated | Yes | No | Yes | Yes | No | Limited | Residential (API-first) |
Deployment and Licensing
| Tool | License | Self-Hosted | Cloud/SaaS | Pricing Model |
|---|---|---|---|---|
| CoreLogic | Proprietary | No | Yes | Enterprise subscription + per-query |
| ATTOM | Proprietary | No | Yes | Tiered API plans ($250–$5,000+/mo) |
| Zillow | Proprietary | No | Yes | Free tier; paid for commercial use |
| CoStar | Proprietary | No | Yes | Enterprise subscription ($10K+/yr) |
| Redfin | Proprietary | No | Yes (consumer) | Free (consumer); no data API |
| Reonomy | Proprietary | No | Yes | Enterprise subscription |
| Black Knight | Proprietary | No | Yes | Enterprise subscription |
| First American | Proprietary | No | Yes | Enterprise subscription + per-query |
| HouseCanary | Proprietary | No | Yes | Per-query API tiers |
| Estated | Proprietary | No | Yes | Per-query ($0.10–$0.50/lookup) |
Integration Targets by Customer Vertical
- Mortgage lenders: CoreLogic, Black Knight, First American (AVM, title, tax data)
- Real estate brokerages: Zillow, Redfin, CoreLogic (MLS data, AVMs, comps)
- Insurance carriers: CoreLogic, ATTOM, First American (property attributes, flood, hazard data)
- Commercial RE investors: CoStar, Reonomy (market analytics, ownership data)
- PropTech developers: ATTOM, HouseCanary, Estated (developer-friendly APIs)
Tools
10 tools.
ATTOM Data
ATTOM Data Solutions is a leading provider of property data APIs focused on making real estate data accessible to developers and businesses.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
Black Knight (ICE Mortgage Technology)
Black Knight, now part of Intercontinental Exchange (ICE) as ICE Mortgage Technology, is a leading provider of mortgage data, property records, and servicing technology for the US mortgage industry.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
CoreLogic
CoreLogic is the largest property data and analytics provider in the United States, covering over 99.9% of US properties with data from 3,100+ counties and 600+ MLS boards.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
CoStar Group
CoStar Group is the dominant provider of commercial real estate data and analytics, covering over 6 million commercial properties across the US, Canada, UK, and Europe.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
Estated
Estated is a developer-focused property data API company that provides clean, standardized access to US property data including parcel information, owner details, property characteristics, and valuations.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
First American Data & Analytics
First American Data & Analytics is the data and analytics division of First American Financial, one of the largest title insurance companies in the United States.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
HouseCanary
HouseCanary is a residential property data and analytics company that provides automated valuation models (AVMs), property data APIs, and investment analytics for the mortgage, insurance, and real estate investment industries.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
Redfin
Redfin is a technology-powered real estate brokerage that combines proprietary listing data, the Redfin Estimate AVM, and a consumer-facing search platform.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
Reonomy
Reonomy is a commercial property intelligence platform that uses AI and machine learning to aggregate, clean, and enrich commercial real estate data from multiple sources.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: OIDC
Zillow (Zestimate / ZTRAX)
Zillow is the most recognized consumer real estate platform in the United States, with over 200 million monthly unique visitors.
License: Proprietary (proprietary) · Kind: web · Deploy: saas · SSO: none
