Watching an MLS feed for the day it goes quiet
A replication loop asks for everything changed since a stored timestamp, then follows the next link until the pages run out. When a credential rotates, or a board moves an endpoint, or an agreement gets re-signed, that loop can return an empty page instead of an error. Nothing breaks loudly. The site keeps serving the listings of last week, sold property sits there as active, and the first report comes from a seller who noticed. What deserves watching is the watermark, which should always be advancing, plus the change count per board against its own normal.
A brokerage runs on dates that were calculated by a person reading a contract, and on leads that arrive in a different shape from every portal.
The listing data is already structured. It lives in the MLS, and since RETS was retired the modern way to reach it is the RESO Web API, which returns OData against the RESO Data Dictionary. Almost nothing else in the transaction is structured. The purchase agreement arrives as a signed PDF that was structured data inside the forms platform ten minutes earlier and got flattened on the way out.
- MLS via the RESO Web API
- Slack
When this is the wrong thing to build
Pick something else if your vendor already publishes feed health with a timestamp per board, which the larger aggregators do. Watching it yourself also assumes you can act, and where the only remedy is a support ticket to the board, what you have bought is earlier knowledge rather than a fix.
The constraint that shapes it
Negotiating, advising on price or terms, and soliciting are licensed activities performed under a supervising broker. More on how this sector works.
No alarm goes off when a thing simply stops arriving. Read what this shape is, or start from one of these.
- Catching a lapse date nobody put on a calendar
- Closing the registration window before it closes you
- Scheduling the visits a membership already promised
- Closing the permit that never got its final inspection
- Noticing a broken bank feed the day it breaks
- Noticing a transmitted return that never came back accepted
- Why did my IDX listings stop updating without any error?
- How do I monitor a RESO Web API replication for silent failure?
- What happens when MLS feed credentials rotate?
- Why are sold listings still showing as active on my website?
- How do I tell whether an MLS feed is actually still running?
Back to real estate, or see how this is priced and scoped.