Thanks. I think this api is best for research and analytics purpose.

Hello,

This API reproduces PUBLIC data and features of the official site/application.
For commercial purposes, the answer is both Yes, and No. You should :
_ Check the local law, it differ between countries
_ Selectively choose which data to use. There are lots of sites providing similar information and they are also collecting data from many sources somehow, and it will be safe if your site is among them. In addition, if you simply clone everything to make a site as same as Realtor.com, you will violate DMCA policy
_ Have data wrapped in another service.

For example,
There are users using our financial API as a feeding source for their AI bots, the bots store and use data to analyze and speculate stock investment trends.
There are users collecting house prices for their own pricing estimating tool.
Google search engine and its advertising business is also another good example, the engine crawls data from sites first for its business.
Remember that you are not allowed to use the branding or trademark. You will be forced to take it down in the future when your site/application becomes famous.

Regards.