RETS Access: Time-saving questions to ask your MLS

Getting a data feed for real estate listings can be challenging if you’re new to real estate technology and how MLSes handle data access. Knowing what to expect and what questions to ask can help save you a lot of time and help get your project started sooner.

First, make sure you know the type of data feed you need. I highly recommend reading my post on the different types of IDX feeds here. I’m going to cover RETS specifically, as it’s the only widely used feed that has raw listing data You need to make sure you ask for RETS access if you want listing data in a raw format for importing into your web site or application.

It’s important you specify RETS, don’t take your real estate client’s word for it! If they say “oh I have a login don’t worry”, don’t believe them unless they say the magic word (RETS). A lot of times they’ll assume you’re talking about their MLS login, which is the login they use to add properties and run searches for clients. Getting RETS access a separate login they have to get from their MLS.

Who should you talk to at the MLS?

Finding the person to contact at the MLS can be tricky, a lot of MLS websites don’t have contact info that spells out how to ask for RETS credentials. Your client help you in this case because they should have a contact at their real estate association or MLS who can get the process started. Again explain you’ll need RETS access. Once you know the contact here are the things you should when you apply for credentials.

Is there a Data Dictionary RETS login available?

The Data Dictionary (DD) is an initiative from the Real Estate Standards Organization to standardize property data across multiple MLSes. Usually MLSes will store their data in a wide variety of schemas, often no two MLSes are the same, even if they’re storing the same kinds of common information. Here’s a description from

The Data Dictionary serves as the real estate industry’s “Rosetta Stone” for real estate data. Hundreds of MLS, and other source providers, gather data. But what good is it if the data cannot be shared or understood? The Data Dictionary ensures that each system “speaks” the same language. It is the common standard that defines real estate data in consistent terms and data structures; a template data providers may follow to format its most common fields.

A lot of MLSes have certified under Data Dictionary, but not all have made it available for their RETS feeds yet. Or they may have a DD feed available, but you have to specifically ask for it. The Real Estate Standards Organization maintains a list of Data Dictionary certified MLSes here.

Even if the MLS has a DD feed, anticipate having to explain what Data Dictionary is when you ask. At a RESO conference one presenter on stage told us a story that they spent ten minutes on the phone with their MLS support contact explaining Data Dictionary and it was only until they said the abbreviation “DD” that the MLS support person perked up and said “Oh the ‘DD’ feed, we have that! Why didn’t you say so?”

Anyway if you can get a Data Dictionary feed now your life will be much easier when it comes time to import the listings, especially if you plan on importing from more than one MLS.

Is there a data licensing agreement? Are there vendor fees?

Be prepared to sign a three way data licensing agreement between you, your client (usually a brokerage) and the MLS. Also some MLSes will charge a vendor fee for access. The fee can vary widely between MLSes. If you’re working as a consultant for a single client be sure to explain that to your MLS. A lot of MLSes will charge a vendor fee assuming you’re building a solution you’re going to resell to multiple customers. If you’re working for a single client you can ask for the fee to be waived.

Are there IP restrictions or separate User-Agent username or password requirements?

Some MLSes restrict RETS connections by IP address, and a few others require not only the standard RETS username and password, but an additional set of username and passwords (called User-Agent credentials). Don’t ask me why User-Agent credentials are required by some MLSes, I don’t understand it either. Fortunately the libraries that connect w/ RETS servers all support adding User-Agent credentials.

What are the query limits on the server?

A lot of MLSes restrict the number of records returned by a query at any one time. Also they may restrict how many simultaneous connections can be open on the RETS server. Knowing about these can help you plan your import process to keep errors down to a minimum. It’s typical to see limits of around 3000-5000 records at a time. Fortunately, most MLSes that limit the number of records also allow you to easily use an offset parameter to paginate through records.

Can we be put on the mailing list for any maintenance updates or alerts?

It’s a good idea to be on the mailing list when the MLS decides to update their server or perform a planned outage. MLSes do update their systems regularly with new fields and changes. Being on the email list can help you keep ahead of any changes before they break your import.

Also make sure you have the support email address saved and any documentation links the MLSes gives you when you get access. A lot of support is handled through email, so having the MLS or RETS server support email address is really important if you run into any issues.


This is by no means a complete list of what to expect from a particular MLS when you ask for RETS access. I’ve integrated with over two dozen MLSes across the US and Canada and I’m still surprised occasionally by access rules and requirements from some MLSes. Let me know if you think I’ve missed anything or need to explain something further in the comments!

If you have RETS access already and need help importing the data or turning it into something you can use for your business, check out my service, or send me an email at