What is IDX and why is it important? IDX (Internet Data Exchange) is how MLS listings end up on a website. IDX encompasses the policies, rules, and software that allow listings from the MLS database to be displayed publicly. Anytime you see properties on a website that came from an MLS, it was made possible through  IDX. Not all sites have IDX so their listings are often out of date so when you call on them they are already under contract. My website has IDX so the listings on there are as up-to-date as the MLS (Multiple Listing System). Feel free to look at listings any time at TallahasseeDestination.com