When I built a website in Wordpress, I must use reCAPTCHA in contact form. Unless, my client will get a lot of spam. Recently, Google migrated All reCAPTCHA Services To Cloud Platform. The UI is changed. Moreover, that is using API key, rather than a secret key. But it won't work in Wordpress reCAPTCHA plugin and Contact Form 7 (that is a common confract form in the custom templates). You still need to have a secret key. Then you click "Use legacy key" in integration tab. I put the screen shot