What is IDX:
The simple definition: For US real estate agents and brokers, Internet Data Exchange (IDX) is the system that allows REALTORS® to show MLS property listings on their websites. IDX stands for "Internet Data Exchange", which sounds technical but quite simple from the agent's perspective.

What is RETS:
The Real Estate Transaction Standard (RETS) is a technology used to exchange standardized real estate data between various software systems that handle real estate information. RETS is not a program, nor is it a language. It is a framework that any computer system can adopt to receive data from the Multiple Listing Service (MLS).

What is Vow:
A Virtual Office Website (VOW) is a website that is used to conduct business activities. One example would be a real estate property search site allowing the public to conduct searches of approved multiple listing service properties in a given area under certain conditions

Placed into effect January 1st 2013, San Diego MLS has implemented changes to the terms and conditions of the IDX/RETS program’s stated policies. San Diego MLS is experiencing a significant increase in demand for its data, resulting not only in the creation of data plans with applicable fees but also stricter limits on data usage. Fees are accessed to 3rd party data providers and are based on server access times, amount of listing data downloaded, and photo downloads vs. utilizing a photo URL(s).

San Diego MLS IDX data agreements with applications can be found below. For any questions, email our Data Services Department at


Notice of Change in Listing Input Form Sellers Right to Opt out of the Internet Description of a VOW​​​​​​​

EMAIL selected applications to:


All documents are in Adobe Acrobat Reader format.