RentCast API vs SimplyRETS for AI agents
RentCast API is a self-serve REST API for US property records, value and rent estimates, market data, and active sale and rental listings. SimplyRETS is a developer API and WordPress plugin that turns your own MLS's RETS or RESO Web API feed into a simple REST listings API.
The short answer
- RentCast API: The quickest self-serve way to search active US rentals and for-sale homes with agent contacts, without MLS paperwork.
- SimplyRETS: An affordable, simple REST layer for an agent or brokerage that already has its own MLS data feed.
Side by side
| RentCast API | SimplyRETS | |
|---|---|---|
| Searches | Active sale and rental listings by city or area with filters, plus 150+ million property records, valuations and market trends. | Listings from the MLS feeds you connect: active, under contract, pending and closed; residential, condo, rental, multifamily, commercial and land, plus open houses. |
| Returns | Listing records with address, coordinates, property type, beds, baths, size, price or rent, status, days on market, MLS name and number, history, and listing agent and office. | Listing records with property details, photos, and listing agent and office information when the MLS feed supplies it. |
| Before the first call | A RentCast account and an API key from the dashboard; no MLS membership or license. | RETS or RESO Web API credentials from your MLS; whether you must be an agent or broker depends on the MLS. |
| Free | Developer plan: 50 API calls a month for $0. | Free demo API keys with sample data; no free trial with live data. |
| Paid | Foundation plan: $74 a month for 1,000 requests. | Basic plan $49 a month, plus a one-time $99 fee per MLS connection. |
| Acting on a result | Listings include the listing agent's and listing office's name, phone, email and website; no landlord contact is described. | Listing agent and office contact details come with each listing when the MLS feed has them, and some MLSs require showing them. |
| Limits on keeping or showing results | The API terms allow storing API data in your own systems and redistributing it only as the license section permits; no attribution is required. | Only listings flagged for IDX display are served, and you must follow the display rules (e.g. last-updated disclaimers) set by your MLS. |
| Coverage | US nationwide; listings are gathered from public sources, not directly from MLSs. | Whatever MLS you connect (US); no fixed national coverage. |
| MCP server | Official hosted MCP server: https://developers.rentcast.io/mcp | 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 RentCast API?
A RentCast account and an API key from the dashboard; no MLS membership or license.
Is RentCast API free?
Developer plan: 50 API calls a month for $0.
What do I need before I can use SimplyRETS?
RETS or RESO Web API credentials from your MLS; whether you must be an agent or broker depends on the MLS.
Is SimplyRETS free?
Free demo API keys with sample data; no free trial with live data.
Sources
Every line about another company comes from its own pages. Prices and terms change, so check the source before you rely on one.
RentCast API, read on October 15, 2026:
- rentcast.io/api: “Our pricing plans start with 50 free API calls per month”
- rentcast.io/api: “$ 74 Per Month”
- rentcast.io/api: “Active sale and rental listings across the country.”
- developers.rentcast.io/reference/introduction: “To get started, create a RentCast account to access your API dashboard and generate your first API key.”
- developers.rentcast.io/reference/introduction: “We have nationwide coverage for most residential properties and select commercial property types in the US”
- developers.rentcast.io/reference/property-listings: “the names and contact information of the listing agent, the listing office or broker”
- developers.rentcast.io/reference/property-listings: “we do not retrieve our property listing data directly from the MLS”
- rentcast.io/terms-api: “and (v) to incorporate and store the API Data within your internal systems”
- rentcast.io/terms-api: “neither use of the RentCast API nor use of the API Data requires attribution”
- developers.rentcast.io/reference/ai-tools: “The RentCast API MCP server is hosted at https://developers.rentcast.io/mcp.”
SimplyRETS, read on October 15, 2026:
- simplyrets.com: “These are our demo API keys, you can use them!”
- simplyrets.com: “Each RETS or RESO Web API connection requires one time $99 connection fee.”
- simplyrets.com: “Get RETS or RESO Web API credentials from your MLS”
- simplyrets.com/faq: “This is dependent on the MLS area you want to connect to.”
- docs.simplyrets.com/topics/fields-and-features-for-idx-compliance: “In some cases it may be required that you show the contact information for the listing agent and/or listing office.”
- docs.simplyrets.com/topics/fields-and-features-for-idx-compliance: “in many areas it’s required to show the timestamp of when the data was last updated in a disclaimer.”
- simplyrets.com: “Basic $ 49 /mo”
- simplyrets.com/faq: “We don't currently offer a free trial period with live data”