Google Invisible reCaptcha
From PeepSo Docs
1. Go to PeepSo -> Configuration -> General to enable reCaptcha.
2. Go to https://www.google.com/recaptcha/ to register a new site and get the keys.
3. Copy the Site Key and Secret Key to PeepSo settings.
Starting from 1.8.6 version PeepSo is using Google INVISIBLE ReCaptcha. If you used ReCaptcha prior to this release you need to generate NEW API keys for ReCaptcha to work on your site. Click [here] to generate ReCaptcha keys.