Craft plugin for input fields on the front end to check existing user I am trying to create a functionality in Craft where the user enter an email and the system is able to tell the user if the user exists or not similar to the attached screen:


I am very new to plugin development, and I am not even sure if I need one, I found this post, which looks very helpful, only thing is I really don't know how to implement it.
How to tell if user exists

Should I develop a plugin? And I don't understand the information on plugin website and I can't find an example where there is an input field on the front end.
If you are creating these as actual users in Craft, it should be possible to do it straight from the template without the need for a plugin, as long as you have Craft PRO (without PRO you anyways wouldn't be able to create more than one "admin" user, and one "client" user anyways):

See the documentation here:
https://craftcms.com/docs/templating/craft.users#email

Basically, you should be able to call craft.users.email('your.email@address.com') to check if it exists. Again, I haven't tested this myself, but it will then return the user if it exists, and otherwise I assume it will return null.