HouseBot

What it does

Runs your criteria against Redfin, Zillow, Craigslist, Facebook, MLS and ApartmentList twice a day, so a listing that appears and disappears inside an afternoon still reaches you. It runs on a schedule rather than waiting to be asked.

Before you install

Open the share link and read the instructions it carries before you add it. @shubgaur shared this one publicly, and adding it copies the setup into your own account rather than giving you access to theirs.