How to calculate the number of API request in a code?

Hi all,
I am trying to write a Python3 code to take some inputs and send SMS, Email to alert. But was not sure what should be the delay duration.
Is every digitalRead/Write an API request?
I am using Twilio and Mailgun to SMS and Email (as in the training), are those API requests considered in the rate limiting?
If I am using Google Assistant to activate/ deactivate the system using IFTTT, is that an API request too?
What are other commands that are an API request?

I am attaching a screenshot of a code, how many API requests are present in the code and what are those?
Screenshot%20(214)_LI|690x422

API Introduction

This should clear your query. If you still have any doubts, feel free to share it out.
Always here to help.