Home monitor keypad question

The nice thing about SmartThings is you can pretty much build any system you want using a wide range of components.

You can use the built in STHM security monitoring app for basic monitoring with the standard sensors.

You can complement STHM or replace with this app which allows for expanded use to monitor more things (like Garage Doors) and use a variety of other devices like keypads or switches to arm/disarm the app. You can do entry/exit delays, You can also have the app do a countdown for you if you have TTS devices (like Bose, Sonos, Alexa etc). And the list goes on but you’re getting the idea by now on how flexible SmartThings can be with the right devices and apps:

If you want to use keypads to arm/disarm you device (or even use their build in Sirens or countdown timers), here are a couple of popular options to consider (there are about 8 different keypads supported between these two topics):