Captcha and Zoho REST API

Captcha and Zoho REST API

I am new to Zoho Creator and I wanted to use Captcha screens in my form validation settings and make a HTTP POST request to Zoho REST API in App Inventor 2 to add, delete and update records. What link name do I need to use for the verification code in my requests - VerificationCode and captcha didn't seem to work? If I use a web viewer to view the Captcha image in a published form can I use its value and pass it as a parameter to a separate POST request to the REST API?