Human verification

Question

I am trying to verify that the user is a human and not a bot. I've tried to scrounge for information on cross platform use of reCAPTCHA, but can't find anything that works for my application.

Are there any ways to do human verification?

For context, the application is a simple form submission that has no login, so there's no username/password to authenticate. I just want to be able to implement reCAPTCHA, etc on submit.