Zillow (Bridge API) vs ATTOM Property API for AI agents
Zillow Group's developer portal lists APIs such as MLS Listings (served through the Bridge Listing Output platform), Public Records and Zestimates, and the listings and public records APIs are invite-only. ATTOM Property API is a REST API for US property records: ownership, sales history, valuations (AVM and rental AVM), mortgages, schools, crime and neighborhood data.
The short answer
- Zillow (Bridge API): Brokers and approved vendors that already have MLS relationships and want a RESO-normalized feed from Zillow's Bridge platform.
- ATTOM Property API: Deep public-record and valuation data on any US property, rather than finding homes currently on the market.
Side by side
| Zillow (Bridge API) | ATTOM Property API | |
|---|---|---|
| Searches | MLS listing data from the MLS partners connected to Bridge; a separate Public Records API covers parcel, assessment and county transaction data. | Properties by address, parcel number, ATTOM ID or latitude/longitude; the docs describe last sales, sales history and valuations, not active for-sale or rental listings. |
| Returns | JSON listing records normalized to the RESO Data Dictionary (MLS Listings API). | JSON or XML property records with characteristics, ownership, sale history, AVM values and area data. |
| Before the first call | An invitation: you request access through a form, and every MLS partner decides whether you get its data. | A trial sign-up to receive an API key; production plans through ATTOM. |
| Free | – | 30-day free trial with an API key. |
| Acting on a result | – | Nothing: no agent, landlord or listing contact fields are described. |
| Limits on keeping or showing results | – | Use of data is governed by a separate license agreement that is not published on the site. |
| Coverage | US and Canada, but only for MLSs that partner with Bridge and approve you. | US, 160+ million properties. |
| MCP server | – | ATTOM MCP Server (access arranged through ATTOM): https://www.attomdata.com/solutions/delivery/mcp-server/ |
Where Openpath fits
Openpath has no homes listed yet. Owners and landlords can list a home for rent or sale on Openpath today, free, and agents will find it through the same search as jobs and businesses. Get listed.
Questions people ask
What do I need before I can use ATTOM Property API?
A trial sign-up to receive an API key; production plans through ATTOM.
Is ATTOM Property API free?
30-day free trial with an API key.
Sources
Every line about another company comes from its own pages. Prices and terms change, so check the source before you rely on one.
Zillow (Bridge API), read on October 15, 2026:
- zillowgroup.com/developers/api/mls-broker-data/mls-listings: “The Bridge Listing Output platform allows brokers and developers to access MLS listing data via a modern RESTful API.”
- zillowgroup.com/developers/api/mls-broker-data/mls-listings: “The platform is currently invite only, so please contact us for the latest list of available MLS integrations.”
- zillowgroup.com/developers/api/mls-broker-data/mls-listings: “All data access is at the discretion of our individual MLS partners in the US and Canada.”
- zillowgroup.com/developers/api/public-data/public-records-api: “This resource is really for commercial use cases by businesses.”
ATTOM Property API, read on October 15, 2026:
- attomdata.com/solutions/property-data-api: “Sign up for a free 30-day trial to receive an API key and explore ATTOM’s extensive property data”
- attomdata.com/solutions/property-data-api: “Covering 160+ million U.S. properties and 99% of the U.S. population”
- attomdata.com/solutions/property-data-api: “ownership information, lat/long, square footage, loan types, sales history, sales comps, crime, schools and more”
- api.developer.attomdata.com/docs: “return information pertaining to the most recent sale of a property or list of properties”
- attomdata.com/solutions/property-data-api: “The ATTOM MCP Server provides AI-native access to ATTOM Intelligence through the Model Context Protocol (MCP).”
- attomdata.com/solutions/delivery/mcp-server/how-it-works: “Access is governed, permissioned, and centrally managed”
- attomdata.com/terms-of-use: “subject to the terms of a separate license agreement”