CAPTCHA is an acronym for "Completely Automatic Public Turing Test to Tell Computers and Humans Apart". It is a task, that human can easily solve, but computer not.
It is used as a challenge-response to ensure that the individual submitting information is a human and not an automated process. Typically, a captcha is used with form submissions where authenticated users are not necessary, but you want to prevent spam submissions.
hcaptcha is a free, easy-to-use WebService helps enterprises to integrate Captcha into their own business systems. Similar to Google reCaptcha but can be customized and deployment to your private network.
LVS -> Hooto Captcha Cluster -> Memcached Cluster