There is no established convention or standard for representing snooze over IMAP. There’s not yet any consensus on how to represent it in JMAP, the emerging standard that we’re backing (and which our web UI will be using fairly soon), either. It’ll be a FastMail-specific JMAP extension at first, but it could well be standardised (though not in the core spec) after that. We’ll see how things go.
Out of interest, why would this be so? On the face of it a single client can keep its own snoozing metadata and use a helper process to do the work. I suppose if you want to ensure snoozing works across clients, you'd need a slightly clumsy workaround for the metadata (eg. encoded somewhere in the snoozed mails in a special IMAP folder). But it looks doable from the perspective of a shallow moment's thought. Admittedly, pretty much everything generally does.
But if your longish snoozes end at the same time, you can use a flag.
(IMAP's cache semantics say: If you download a part of the message it stays valid. Other people cannot change what you have downloaded.)
And I'm also thankful that I trade mail with far fewer designers these days.
At least on Mac there are some client side only ones:
- https://canarymail.canny.io/
- MailTags for Mail.app has a “tickle” feature that meets all the requirements
That is from a few minutes searching.
Google Inbox is a better UI, but goes too far the other way towards wasting too much space. It's also missing some key features, and is still not a desktop client.
Also, neither one of them supports showing emails from multiple gmail accounts in a single inbox (unless you just blindly forward emails from one to the other, which you can do, but I'd rather avoid).
I recognize I'm being very picky here; mostly what I just want is Dropbox's Mailbox app, but they killed that off long ago, much to my eternal disappointment.
Imagine you read emails in an unread folder, where read emails disappear. This basically would functionally mark them as read until a preset amount of time passes, then they show up as unread again. It's a bit like that, only in your inbox itself.
It's not actually a part of the email specifications, but some people seem to like it.
It doesn't require a third-party server. Nylas did do it that way, but Mailspring aren't. It's local.
I'm curious, such as what?
For the record, my needs in a mail client are: GUI, very clean UI, pretty themes, good search, works with gmail, ideally supports snoozing emails (a key feature if you like to pursue Inbox Zero), if at all possible should be a desktop app for OS X and Windows, and I wouldn't be adverse to open notifications and such. Also, I'm explicitly fine with their being an extra server in the mix; this is more-or-less required for snoozing emails to work properly[1], and I'm not really concerned about privacy.
If that describes you, you might like Mailspring too. If not (and I suspect that'll be the case for the median HN visitor), then probably not. :)
Edit: Totally forgot, I also have a strong need for supporting multiple email accounts. A merged inbox view that will automatically use the correct email address/signature for replying to an email based on where the original email was sent is critical.
[1]: At least, every implementation of email snoozing I've seen had relied on a third party server. And once I got addicted to it with Dropbox's much-mourned Mailbox app, I've found it very hard to use a mail client without it.