Is it possible to send sms/email requests only by using HTML/JS on cloud.boltiot.com?
Can I use digitalRead/analogRead to trigger this request?
yes, it is possible to send sms or email using HTML. HTML is generally better for marketing emails.
Yeah you can send through Java Script cuz is a high level programming language just like Python. Mailgun as their own Node Js module for that purpose Check out the documentation