That depends on what you mean. If you mean, "Is it possible to have SMTP without a server?" the answer is no, by definition. SMTP is a client-server protocol. The same is true of IMAP and POP.
If you mean, "Is it possible to have something that has an email-like UI/UX without a server" the answer is yes. But it won't interoperate with what we call email today, because that is fundamentally based on SMTP.
In fact, the original email was serverless because it only worked on a single machine. That protocol is actually still in use today. Cron jobs error logging message of last resort is to send email to root@localhost, which is done without any networking at all.
If you mean, "Is it possible to have something that has an email-like UI/UX without a server" the answer is yes. But it won't interoperate with what we call email today, because that is fundamentally based on SMTP.
In fact, the original email was serverless because it only worked on a single machine. That protocol is actually still in use today. Cron jobs error logging message of last resort is to send email to root@localhost, which is done without any networking at all.