Similar - POP Peeper

I am a newbie on mac. at this moment I am installing some softwares. So far, I am looking for a software like POP PEEPER. After looking at the website, I noticed that there is no POP PEEPER for mac, but if someone knows any similar like this, I would appreciate it a lot for receiving any information. BTW, the idea it is not to create an email account on MAIL.app, and the messages cannot be removed from the email server, however I can see (preview) the emails, or delete the message, if it is the case. I am not sure if it is clear, but let me know.

thanks.