Listing data
MLS (Multiple Listing Service)
Also called: Multiple Listing Service
An MLS, or Multiple Listing Service, is a database of property listings maintained by a real estate board or association, through which member brokerages share listings with each other and agree terms of cooperation. There is no single national MLS in Canada; boards operate regionally, each with its own membership, rules, and data.
Because boards are regional, an agent's data access follows board membership. A site displaying listings from several boards is drawing on several separate agreements, not one national feed.
The MLS is the source that IDX and VOW arrangements draw from. The distinction between them is about who may see which fields under what conditions, not about different databases.
Data accuracy questions belong to the board and the listing brokerage, which is why display rules generally require attribution and a stated refresh frequency.
An agent moving to a new brokerage or expanding into a neighbouring market has to confirm board membership separately, since a listing agreement with one board does not carry over to another. A website built to display MLS data needs to know which boards it is actually drawing from, not just that the agent has MLS access somewhere.
Why it matters
Board-by-board membership decides which listings an agent may legally display, so coverage is a real constraint on what a site can show.
Related terms
Last reviewed 2026-09-04. All Saige glossary terms.