Determine whether a real estate website integration needs IDX or VOW-level MLS data access before requesting a feed
domain: nar.realtor · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Confirm whether end users of the site will be anonymous consumers (IDX) or registered/logged-in consumers with an established broker relationship (VOW)
Review the local MLS's IDX and VOW policies, both generally modeled on NAR's Handbook on Multiple Listing Policy, since specific opt-outs and data fields vary by MLS
For VOW, implement mandatory user registration/login before displaying any VOW-only fields such as sold/expired listings
Request the corresponding data license (IDX or VOW) from the MLS separately from the technical feed, since the license and the RESO Web API/RETS transport are granted independently
Configure field-level suppression per the granted policy (e.g., hiding broker remarks or showing agent opt-out flags) before going live
Known gotchas
IDX and VOW are legal/policy distinctions about who may see what data and under what consumer relationship, not technical protocols — the underlying transport (RESO Web API) is the same for both
VOW feeds typically include additional historical data (sold, expired, off-market listings going back years) that must never leak into a public IDX-only display
Each MLS's IDX/VOW rules are its own policy variant on the NAR model policy, so a compliance approach validated for one MLS cannot be assumed to satisfy another MLS's rules
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