Zillow (Bridge API) vs Spark 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. FBS's Spark API and RESO Web API give authorized applications access to MLS data on the Flexmls/Spark platform.
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.
- Spark API: Apps built for agents, brokers or MLSs that use Flexmls, where the MLS member authorizes access.
Side by side
| Zillow (Bridge API) | Spark API | |
|---|---|---|
| Searches | MLS listing data from the MLS partners connected to Bridge; a separate Public Records API covers parcel, assessment and county transaction data. | MLS listings (and, for VOW apps, sold data) from participating MLSs, within the roles each MLS grants. |
| Returns | JSON listing records normalized to the RESO Data Dictionary (MLS Listings API). | MLS listing records in Spark or RESO Web API format. |
| Before the first call | An invitation: you request access through a form, and every MLS partner decides whether you get its data. | A free developer account, then an MLS data plan or an MLS member who authorizes your app. |
| Free | – | Developer account sign-up is free. |
| Paid | – | $50 a month for each MLS you access, once you have data from your first MLS (MLS data plans may set their own terms). |
| Limits on keeping or showing results | – | No storing MLS content except temporary caching for performance, unless your key permits replication; MLS display rules and license terms apply. |
| Coverage | US and Canada, but only for MLSs that partner with Bridge and approve you. | Participating MLSs on the FBS platform; no list or count on its pages. |
| MCP server | – | No official server listed |
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 Spark API?
A free developer account, then an MLS data plan or an MLS member who authorizes your app.
Is Spark API free?
Developer account sign-up is free.
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.”
Spark API, read on October 15, 2026:
- sparkplatform.com/docs/overview/api: “The Spark API allows authorized MLS members to request data through developer applications”
- sparkplatform.com/docs/overview/api: “When IDX applications are purchased, the MLS member must authorize that application to access their data.”
- sparkplatform.com/docs/overview/faq: “It’s free to sign up for a Spark API developer account.”
- sparkplatform.com/docs/overview/faq: “Once you have access to data from your first MLS, API access costs $50/mo for each MLS you can access.”
- sparkplatform.com/docs/terms_of_use/developer_agreement_and_terms_of_use: “except for temporary caching purposes necessary for performance enhancement”
- sparkplatform.com/docs/terms_of_use/developer_agreement_and_terms_of_use: “Compliance with MLS Rules and License Terms regarding MLS Content”