I send out a personal email newsletter, and have been looking into sending it via some service like MailChimp, or sendy.co. Many of these email services suggest, or require, the email newsletter content to be available online, in case the recipient's email app doesn't render it properly, or at all.

The thing is I don't want my newsletter contents visible to the whole world. Nor do I want to require existing recipients to make accounts/be assigned accounts, with passwords. So, the question is:

How can my WordPress site content be viewable only by clicking on the link to it in the email newsletter.

It can't be found in a Google search; but once at the site the visitor can view previous newsletter contents. It seems an .htaccess file would do the trick, but I have been unable to figure out the syntax for this.

Thanks for your help.

I have copied below two other questions, and answers, which have helped me word my question clearly.

Similar to this request about allowing access to a certain group while still restricting access to the world: Is there a way to password protect directory only in cpanel. But the user should not be prompted the password, when they try to access it via web?

This persons question is the closest I could find to my situation: Restrict direct folder access via .htaccess except via specific links