All our forms (hosted, iframe and HTML) are automatically protected by reCAPTCHA. Nothing is required from you to activate this protection.
This is an invisible reCAPTCHA and it will only appear if your subscriber’s behaviour seems suspicious. In some cases, they may have to solve a puzzle to confirm that they’re not a robot in order to complete their subscription. You can't deactivate this protection.
If you are planning on getting an unusually large number of subscriptions on your website (e.g. from a tradeshow), to avoid the frequent appearance of CAPTCHA, we recommend that you use a form programmed with our API. You will still need to let us know about your event so that we can make the necessary arrangements.