Spark API vs Zumper for AI agents
FBS's Spark API and RESO Web API give authorized applications access to MLS data on the Flexmls/Spark platform. Zumper is a US rental listings marketplace; its developer-facing offering is an inbound feed for property managers to send listings to Zumper, not an API to read listings.
The short answer
- Spark API: Apps built for agents, brokers or MLSs that use Flexmls, where the MLS member authorizes access.
- Zumper: Getting rental listings in front of renters (including inside ChatGPT) for property managers, not reading listing data.
Side by side
| Spark API | Zumper | |
|---|---|---|
| Searches | MLS listings (and, for VOW apps, sold data) from participating MLSs, within the roles each MLS grants. | – |
| Returns | MLS listing records in Spark or RESO Web API format. | – |
| Before the first call | 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). | – |
| Acting on a result | Not stated on its pages | On Zumper itself, leads and tour requests go through Zumper's listing pages, including from its ChatGPT app. |
| 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 | Participating MLSs on the FBS platform; no list or count on its pages. | US rentals |
| 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.
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”
Zumper, read on October 15, 2026:
- zumper.com/manage/premium-listings: “Listings automatically posted to our partners: PadMapper, Microsoft Bing, Realtor.com, Chat GPT/Open AI, and more.”
- zumper.com/manage/resources/zumper-chatgpt-app: “All leads, tour requests, and renter actions continue to flow through Zumper's existing listing experience and reporting.”