Obvious implementation: use IMAP to create a folder, snooze-$timestamp. Move messages there. Every so often, check the snooze-$timestamp folders and present every one where the timestampt has expired as part of the unread group. Delete empty folders.

> - It still has the same great pro features, like snoozing and send later, but doesn't send your email credentials to Mailspring servers. All of these features have been re-implemented to run locally on your computer.

It doesn't require a third-party server. Nylas did do it that way, but Mailspring aren't. It's local.

Yeah, it seems easy enough to do client side unless one wants it to be synchronized across devices. Then, I imagine it'd be easy for the email provider to do, though it'd need client support or to be in the browser.