What the MLS actually is
The MLS isn't one thing — it's hundreds of regional databases, each operated by a local Realtor association or a private MLS company. Each MLS has its own:
- Geographic territory (a metro, multiple counties, sometimes a whole state).
- Membership rules (most require a real-estate license and Realtor association dues).
- Data fields and rules (though RESO Web API standards have pushed convergence).
- Coverage of niche listings (rentals, commercial, land — some MLSs include all, some are residential-only).
Major examples in 2026:
- California Regional MLS (CRMLS) — largest MLS, ~110,000+ members.
- Bright MLS — Mid-Atlantic (DC, MD, NJ, PA, VA, DE, WV).
- Stellar MLS — Florida, ~80,000 members.
- Northwest MLS (NWMLS) — Pacific Northwest, notable for being independent of NAR.
Who has access (and why public sites lag)
Three tiers of access:
- Brokers and licensed agents — full read/write access via the MLS portal. They post listings, edit price changes, see private remarks (often more candid than public-facing description), pull DOM and CDOM, and run instant comp searches.
- Public-facing IDX feeds — what Zillow, Redfin, and Realtor.com use. The MLS sends a filtered feed to syndicators, typically excluding private remarks, exact GPS, full price history, and some condition fields. Refresh cadence is typically 15-minute pings, but the public site's display caches can lag another 12–36 hours.
- Buyers and the public — read-only via the syndicators. Direct MLS portal access is locked down for non-licensees in nearly every market.
The result: public sites are usually 24–48 hours behind the MLS on new listings, status changes, and price reductions. In a hot market that gap is decisive — by the time a listing appears on Zillow, it's already had 8 showings. In a slow market the lag is mostly cosmetic.
What changed in the March 2024 NAR settlement
The Burnett v. NAR settlement (finalised March 2024, rules effective August 17, 2024) didn't open public MLS access — but it did change two MLS-adjacent rules:
- MLSs can no longer require a "cooperating compensation" field as a condition of listing. Pre-settlement, the MLS forced sellers to advertise the buyer-agent commission they'd pay; that field is now removed in NAR-affiliated MLSs (it was never required at NWMLS, which is independent).
- Buyer broker agreements are required before an agent shows any MLS-listed home. This is enforced at the agent level, not the MLS itself, but it changes the buyer-agent workflow that the MLS supports.
What did not change: public direct access to the MLS portal. You still need a licensee to pull a full MLS report, see private remarks, or run a CDOM search. Some MLSs experimented with limited public access (BeycomeMLS, BoldTrail, a few state-level pilots) but as of 2026 the rule is unchanged.
What MLS data shows that public sites don't
Six fields that matter:
| Field | MLS shows | Public site shows |
|---|---|---|
| Cumulative DOM | Yes | Sometimes |
| Private remarks (agent-only) | Yes | No |
| Exact GPS coordinates | Yes | Often masked to street |
| Full price history (incl. relists) | Yes | Mostly yes |
| Days under contract before fall-throughs | Yes | No |
| Showing count / agent feedback | Yes | No |
If you're going unrepresented, the practical workaround is the flat-fee MLS listing service for sellers (which gets a seller on the MLS without paying a listing commission) — but on the buyer side, you mostly rely on the public sites' filtered feed, plus a real-estate attorney or transaction-coordinator who can pull a full report on a specific property.
RESO standards and why they matter
The Real Estate Standards Organization (RESO) publishes the Web API Data Dictionary that nearly every US MLS implements. This is the reason cross-MLS data is even semi-comparable — without RESO, every MLS would have its own "yearbuilt" vs "YearBuilt" vs "yrblt" field name.
For buyers, the practical implication: third-party tools that query RESO-compliant feeds get similar data quality regardless of the vendor brand on top. Tools that scrape public sites get filtered, lagged data. The methodology page on any reputable valuation tool — including Twellie's at /methodology — should state which data sources it uses.
Practical buyer workflow without MLS access
If you don't have a buyer's agent, here's the closest substitute:
- Set up alerts on 2+ public sites. Zillow + Redfin together usually surface most new listings within a few hours of each other.
- Run a paid AVM report on serious candidates. A RESO-feed-based report can surface CDOM, recent comp adjustments, and condition flags the public sites minimise.
- Use a flat-fee transaction agent to pull MLS specifics on a property you want to offer on. They can run the full MLS report for $50–$200.
- Sign up directly with a brokerage's "buyer-rebate" service (Reali, Yoreevo, regional flat-fee brokers). You get MLS-level listings and a partial commission rebate.
See best tools for unrepresented home buyers for the current vendor list.