Permitting for additional bedrooms and garage conversions requires compliance with zoning and building codes.

Then coding the p&l can happen. without the Balance Sheet, I don't know if I am missing transactions.

I can get a list of about 6,000 after applying zip code filters, room count, etc.

Under $150, easy to install and use, tenant can set their own code but landlord can retain the master and always have access, tenant can't lock themselves out, standard key for emergency backup, batteries last a couple years, etc.

By zip code only or zip code + 4 digits?

And the code enforcement back even 10 to 15 years ago was non existent. 

It was actually considered a violation of the Realtor code of ethics to charge anything other than the standard, "fixed" commission rate.

If you're going to rent the space or sell it as livable space, it will need to meet code.

I know you code C++ well enough to create bitcoin. 

Also, you should update your NAICS code as well to align with your new name and business focus.