Nexus Energy Services Inc (IBGR)

[surfkast]

While it varies greatly, the general answer we provide to people asking us how long it takes to build an app is 4-6 months. That does not mean a first version of an app—a v1.0 app—can't be built faster than four months or that it won't take longer than six months. We've done both at Savvy Apps.

https://savvyapps.com/blog/how-long-does-it-take-to-make-an-app

Finally, a quick search of the USPTO shows a multitude of patented real estate apps.

http://patft.uspto.gov/netahtml/PTO/search-bool.html