Does anyone know how many API calls can i make for the google reCaptcha standard.

I already coded and deployed recaptcha essensials and looked into enterpise solution. the latter does not have secret key and completely different from the first one. Here is it says how complicated it is:

https://www.googlecloudcommunity.com/gc/reCAPTCHA-Enterprise/recaptcha-enterprise-is-just-crazy-hard/m-p/703561

How can I choose and deploy recaptcha standard and find sample codes. Does it have secret key on server side validation.

I found this talking about standard plan is introduced recenlty.

https://www.inclind.com/news/google-recaptcha-price-change

I asked this quesiton on community:

https://www.googlecloudcommunity.com/gc/reCAPTCHA-Enterprise/How-to-choose-standard-plan-for-recaptcha/m-p/788351#M195