Every legitimate listing automation, whether it is a distressed property scanner, a CMA tool, or a brokerage dashboard, sits on top of licensed MLS data access. Scraping portals violates terms of service and produces stale, incomplete data. The correct path runs through your own MLS's data access program, and for most MLSs in the United States that means the RESO Web API.
What the RESO Web API Is
The Real Estate Standards Organization defines the standard API through which MLSs provide programmatic access to listing data, replacing the older RETS protocol. Alongside it, the RESO Data Dictionary standardizes field names, so ListPrice, DaysOnMarket, PublicRemarks, and price change records mean the same thing whether your MLS is in Florida or Oregon. This standardization is what makes it possible to build one analysis system that works across markets.
How Access Actually Works
Access flows through your MLS membership. The typical path: the agent or broker requests data access through the MLS's vendor or data licensing program, signs a data agreement defining permitted use, and either receives API credentials directly or works through an approved vendor that already has a feed relationship with that MLS. The agreement matters. It defines what the data can be used for (your own business analysis and client service, generally yes; republishing or reselling the data, generally no), and every system built on the feed has to operate inside those terms.
This is the foundation under the system shown in our distressed property feed demo: it runs on the agent's or brokerage's own licensed feed, pulled daily through the approved API, analyzed privately for the agent's business. No scraping, no third party data resale, nothing that puts the agent's MLS membership at risk. If you can get a data agreement signed with your MLS, the rest of the automation is an engineering problem with a known solution.