Show categories in e-mail notifications

As a standard Discourse user, I want to see standardized indication of the category assigned to a post when I receive e-mail notifications, so I can better prioritize what I reply to and when.

Rationale: We’re working really hard to migrate people from a series of several mailing lists over to Discourse, and being able to specify categories in notifications somehow is pretty important to attracting those people who still want to live in their inbox. If the category were specified in the subject line or an e-mail header, those people, could then automatically filter and sort notifications.

If the e-mail subject were used, perhaps the site name could be moved to the “From” field in a manner such as "downey via My Discourse Instance <>". The subject could then read something like “[feature] Show categories in e-mail notifications”.

Alternative: I know that as of today we can now customize the email_prefix which is a step in the right direction. :thumbsup: Maybe it could be something as simple as the user entering a variable name in the email_prefix setting, so people could still use a “generic” prefix if they wish.


This would especially be useful for Discourse implementations that are replacing mailing lists. This “feature” of mailing lists is fairly common and will be missed.


Sorry, should have updated – this has been in for a week or two already, at least for digest emails.

@codinghorror I just went through the git commits looking for this feature. I saw this

But, that’s not exactly what we are suggesting. As @downey indicates…The subject for the email notification of THIS post would be

Would make the subject awfully noisy. I’m referring to the body of the email – and the digest email in this case. Here’s a screenshot:

FWIW, my original story related to e-mail notifications for watched items, and not the digest e-mail.

There’s already a tag in the subject line. It’s just the same (e.g. installed system name) regardless of the category. My proposal would simply make it more precise.


It’s burying the lede hard though:

So we go from email titles in the form of

[sitename] Topic title


[sitename] [category] Topic title

I just think category can be present in the body – pushing the real, actual title of the topic that far over will make it invisible on mobile mail clients, for example…

Actually if you re-read my first post, you’ll see that I suggested only category in subject, and possibly site name in “From” field, and/or use of headers. People need a standardized way to know what a notification is about because the post title (subject line) is not in a structured format.

No one’s going to open an e-mail to see the category and determine whether or not to read it. By that point, the damage is done and the time is wasted. :wink:


I agree with @downey, it’s a useful feature and something we need to allow replacing mailing lists in our organisation for people who don’t want to use digests exclusively or at all.

If you make email prefix accept flags for %sitename% and %category%, then you can let the admin determine what works best. I know in our case it’d end up being something like [foo-%category%] so it’d end up being like:

[foo-general] Amazing thing happens!

Not verbose, and makes it clear that it’s a category related to that organisation. People can then mute the categories they have no interest in seeing in their preferences and bam, you’ve fully emulated a mailing list.

This is a killer feature for us, basically.


This is a top – if not the #1 – limiter of people moving from our lists to Discourse in our project (1000+ people). If we don’t have a comfortable migration path for people who prefer to live in their e-mail inbox (I’m not one of them) we’re never going to reach critical mass of uptake for Discourse.


I am a member of the Plone community and we are right in the process to switch of the former mailinglists to Discourse. There’s just this culprit left to solve, to get it going.
Filtering mails by categories is uttermost crucial for us, we are already facing huge acceptance problems because of this, and it would be really sad, if all the done work of the people setting up Discourse for us, would have been useless only because of this single issue, besides of missing all the awesome additional features Discourse offers.

Will it be possible soon, to include the category somewhere in mails (preferably in the subject) ?

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I could have quoted a number of posts in this topic for this, but my impression so far of Discourse is that when migrating mailman lists to discourse, each mailman list with its own already email-connected community and established list owners/moderators should get its own discourse install, not just one category in a big discourse install with lots of categories. That way you can let them have full freedom within that community to create whatever categories to organize their discussions and to manage their community rather than forcing them to be part of something bigger and see things from other migrated lists that they potentially have nothing to do with.

The architecture of discourse doesn’t really support the traditional setup where one organization hosts dozens or hundreds of mailman lists, and I’m not sure it’s going to ever make those people happy who just want to live in their email. We can tinker around the edges to make the subject line more customizable, but the tension between what forums need vs what lists need will always be there and I for one would hope that the forum will always win. :slight_smile:

This is a bit optimistic - there are other big differences that people who favor email will not be happy with, like the fact that quoted text and forwarded emails get filtered out and don’t get distributed/make it to the forum. You can’t manage your subscription by email, query mailman servers by email to get info, you can’t deduce the email address to reach the moderator etc.

Is it not already in the body of the message, right next to the post title?

This is not an accurate representation of large projects with multiple lists. In such projects, lists are the categories. Discourse email integration has recognized this allowing unique incoming email addresses per category. Now we’re just asking for parity on the outbound side by allowing users to filter notifications per category using a subject line or email header, just like lists afford.

There is immense cross-pollination value in keeping all the conversation in a project in one place. Identifying email notifications by category helps make that happen for people who want email notifications from Discourse. Splitting lists/categories into multiple installations would be a giant step in the wrong direction.

Thanks for taking the time to explain. Each community has its own internal logic and culture, so I shouldn’t be making any assumptions about yours. :slight_smile: But be prepared to start managing expectations as users start to realize all the things they miss from mailman!

I agree that having the subject line customizable along the lines suggested by @piecritic:

I like this suggestion. If I had this option I would also only put the category in the email subject in square brackets, e.g. [volunteers] for notifications form the volunteers category. If there are no categories, the subject prefix would be left out altogether.

… but for my community what’s on the subject line is not a deal killer, since the categories are highlighted very nicely inside the message.

@eviltrout can you implement a configurable substitution scheme string for email titles this week including {category}, {sitename}, {topictitle}, etc? Just the title of notification emails should be configurable in this manner.


Thanks so much for this. :slight_smile:

OK, clearly @eviltrout has this in hand, so I’ll leave this alone for now (contact me if I can help). Hopefully my comments at Email subject configuration options and/or my pull request code with adding the “Re:” are useful.

I would add to please include with the configurable subject lines the option to include the “Re:” in replies, which I am pretty sure is part of the requirement for to thread properly (stupid though that may be).

Also, with the addition of a List-Id header, there is no real necessity for the [Site Title] in the subject line, which makes the option of just using a subject with just the [category] much more appealing.



I suppose that’s a worthy goal, but keep in mind has only a 7% market share. I don’t know how the other clients handle threading but it’d be worth trying to get it right wherever possible.

That’s true, but it also makes the category unnecessary as well. As I understand RFC 2919 the List-Id should be as specific as possible, e.g. List-Id: <>. This becomes especially true since the system allows unique email addresses for each category. At least that’s how I process it in my mind.

In general, perhaps. For my mailing list, its probably more like 90+%.

Given there are definitely people who have said that they are using or plan to use Discourse in a way where each category is conceptually a separate mailing list, I completely agree that should be an option.

It should be possible to configure Discourse such that it behaves as:

  • A single community, a single mailing list, with a single list ID.
  • A group of communities, a group of mailing lists, each with their own list ID.

In either case, optionally including the category in the subject may be desirable, and optionally not including the site title in the subject may be desirable.


Thanks for getting this started! Has there been some progress by now, can we start to open the champagne-bottles? We’re really eager to kick it off, and tell every Plone-nut about it :sunny:

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