MozillaThunderbird vs KMail how are they different? [Opinion?]

Many years ago, I used KMail as my primary mail client. I don’t believe Thunderbird was even available on Linux. For personal reasons, I have only been able to use Windows for the past several years. On Windows I use Thunderbird as my primary mail client. Now that I’m back on Linux and see that Thunderbird is here, I’m wondering which one I should use.

The email server is IMAP. What are the pros and cons of each mail client? Yes, I know I can (and probably will) use both of them so long as I leave my messages on the server. I’m seeking the insights of others.

Well, I can just tell about MozTb. And I like it. I use both MozFx (as browser) and MozTb (as e-mail client). I especially like them for the possibility of about:config settings (used quite much to modify specific settings due to security or privacy) and adding Add-ons (extensions) for special needs.

One Add-on for MozTb I like very much is DKIM Verifier. Good e-mail providers check DKIM at server side. But it’s nice to have this possibility to check at client side. I haven’t seen this for any other client. This extension is really awesome when you are security and safety aware.

Another Add-on I like very much is Mail Merge. You can send a message to multiple recipients, but personalised. Very nice when addressing a larger group of recipients.

I think, MozTb does provide most of today’s technical functions for an e-mail client. I use IMAP, CalDAV and CardDAV with MozTb to my satisfaction.

Well, GUI is always up to personal opinion. For me, I am fine with.

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I was also working on a mixed windows + linux environment. At that time I had a poor experience with kmail. It brought in a whole set of akonadi-based packages to my Gnome system and occasional instability/ errors. I moved to Evolution and that worked very well.

I have now moved to KDE and use Thunderbird for email and calendar and all seems to work very well

KDE Plasma uses Qt.
GNOME uses GtK.


If GNOME then, use GtK based applications – such as Evolution or Thunderbird.
If KDE Plasma then, use the KDE Kontact suite.

  • But, you can use GtK based applications (Mozilla Firefox and Thunderbird – LibreOffice – etc. etc.) on KDE Plasma Desktops and,
  • You can use Qt based applications (KDE Plasma applications) on GNOME Desktops.

But, you’ll have to accept the additional libraries which will be installed as a result.

@Ljosalfr:

Thunderbird or, Evolution or, the KDE Plasma Kontact suite?

  • Mozilla Thunderbird is simple, reliable, basically an e-Mail client, with an appointments calendar as a plug-in.
  • GNOME Evolution and the KDE Plasma Kontact suite are PIM (Personal Information Management) suites with everything you need for PIM in a Group environment – in other words – @work
    The GNOME Evolution is an alternative to Microsoft Outlook coupled to a Microsoft Exchange office environment.
    The KDE Plasma Kontact suite has integration to non-Microsoft office PIM environments.

Thanks @dcurtisfra, maybe is time to try again Kontact !

I enjoy Thunderbird even though I’m on KDE.

It packs a lot of features but it is still very simple and intuitive to use.

When OpenSUSE became my main OS, I used KMail as I thought it would be the best integrated mail client for the KDE Plasma desktop environment. I had some bugs and it was a bit tricky to set up, but all in all very usable.
However, on my old windows system I had mostly used Thunderbird back in the days and the update to version 115 (Supernova) made me try it again. I quickly stopped using KMail and now only use Thunderbird. It is just amazing. I’m sorry for the KMail developers, but it just doesn’t even compare.

I would say use KMail only if you are eager to tinker and don’t mind a few issues here and there. But if you want a reliable email client, use Thunderbird. It’s worth the few GTK packages, if you don’t already have them anyway.

That’s also a good reason for me running MozTb. I have MS Windows, Apple macOS and Linux (openSUSE Leap and Slowroll) all around. MozFx and MozTb are cross platform available.

And I have an Android smartphone (Google Pixel with GrapheneOS). There, I use K-9 Mail. It’s FOSS. And it’s the new Thunderbird for Android. K-9 Mail joins the Thunderbird family

And I use the Android e-Mail Client supplied by my ISP (United Internet – 1&1) on my Android mobile telephone.

KMail is part of Kontact which offers you a lot more than Thunderbird if you need it; in practice I use the Mail, the Contacts and the Calendar on my desktop but there are other things I could use. Though the Mail is lacking in some ways compared with Thunderbird, the Contacts and and the Calendar are much better for my needs.
I used Thunderbird on my laptop partly because it is much easier to set up for IMAP and I don’t usually need to use Contacts or the Calendar when I am away from home.