Check if another Application is alive

Question

I have an application that runs 24 hours a day generating some data, and it used to crash from time to time when it needed to send the data to a web server. Then came the idea of dismembering into two apps, one generates the data and another transmits.

The question is this, at each cycle of the "main" app, after generating the data, it initializes the secondary app to transmit the data, as I can check if this second application is alive from the past cycle and how to kill it if it is before calling it again?