If you use Thunderbird's built-in chat with an XMPP account, it can't encrypt messages the way phone apps like Conversations and Cheogram do. This free add-on adds that (OMEMO) for one-to-one chats, with a padlock on every encrypted message and verification by fingerprint or QR code.

It also has an optional Chat contacts tab that names chat contacts from your address book.

GitHub (free, open source): https://github.com/precisioncrab/thunderbird-omemo

Also on Gumroad, pay what you want: https://precisioncrab.gumroad.com/l/omemo

It has to be installed from a file, after one Config Editor setting, because Thunderbird's add-on site doesn't accept add-ons that reach into the chat code. Steps are in the README. Tested on Thunderbird 156 and 158 on Windows.

Long story short, it's been a while that I started feeling uncomfortable at the idea of using Gmail as the main address/collector for everything (bank, taxes, healthcare, etc). I also used it as unified inbox for a total of 20+ email accounts and multiple mailboxes.

Being locked out or "incapacitated" for some reason (lost phone, for example) would be an absolute mess. Yes, you can restore and reset stuff, I did it once or twice during my Gmail career, but it's not e pleasant trip, and dealing with Google isn't always a guarantee success.

21 years on Gmail is a long time. Moving to another client wasn't easy. Old habits, shortcuts, you name it. But... I had to do it. Surprisingly, Thunderbird (both desktop and mobile) work noticeably better. All my accounts are IMAP, obviously. My main account is something like [myname@mysurname.com](mailto:myname@mysurname.com) and it's hosted on my own VPS. I own it, I control it, I backup it. If it dies or explodes, I can switch the DNS to somewhere else and I'm online in a minute. Having Thunderbird always synced is great. And boy is it FAST, I love it.

Any tips for a newcomer?

I use it on my desktop/laptop, as well as on 2 Android phones (unified Inbox in both cases). Feel free to suggest anything you think it may help making the experience even better. Thanks!

I'm a Mac user and for years I used Apple Mail. It's an OK mail program.

But I absolutely hate how it deals with attachments. If you have an attachment of a file that Mail can open (PDF, Pages file, image file, etc) it just shows the content of the file in the body of the message.

And if the file type is something Mail can't render natively, then it shows an icon for the attachment IN THE BODY OF THE MESSAGE.

The combination of the two is just horrible UI design.

When I moved away from using iCloud mail to Fastmail with my own domain name, I wanted a new email client. So, I went to Thunderbird, since I had previous experience with using it on Linux. And something just didn't click for me on Mac.

eM Client was on sale on Black Friday. I picked it up and have been using it for almost 2 years now. Version 11 just came out, and when I went back and looked at it's list of features, all of them were AI features that required a subscription. It included an MCP server that didn't require a subscription. But Fastmail runs an MCP server, so I really don't need an MCP server in my mail client.

I could have stayed on version 10, but I took this upgrade as an opportunity to check out other mail clients.

So, I came back to my old friend Thunderbird. And things just clicked this time for me. I'm not gonna lie, as a Mac user, I care about the functionality AND the appearance of my apps. The current default theme was good, but then I installed the CleanUI them, and I liked that a lot better.

Then I set up a style sheet to use the font Inter as the UI font and set the scaling to 2.5, and I was very happy with the UI.

Now it came time to deal with functionality. Thunderbird quickly connected to Fastmail and downloaded all my emails.

Then it came time see what plugins I needed. And this is where Claude Code really helped me out and let me make Thunderbird my own.

The first thing I wanted was to be able to set server-side rules on Fastmail. And I wanted to be able to do it inside of Thunderbird. So, Claude was able to make me a plugin that adds a button to the toolbar. When I click on it, it opens the Fastmail rules page in a separate tab and I can create a server-side rule. Obviously it doesn't let me make rules by simply clicking on a message. But it saves me the trip to the browser.

Then I went on to the FileLink plugins. I installed one for Dropbox, but was a bit disappointed it could not do expiring links. I found the GitHub repo for the plugin, forked it, and had Claude Code add an expiring link option. And I hit a dead end. I get my Dropbox through Lenovo, and it's only a Dropbox Plus account. You need a Pro account.

My next alternative was to use Nextcloud, since I had a Nextcloud server in my house. I found a few Nextcloud plugins, but none of them could do expiring links. So, I fired up Claude Code and spent about 2 hours vibe-coding a Nextcloud FileLink provider that lets me not only create links that expire after whatever time I set it for, but also links that expire right after the person downloads the file. After a ton of bug fix and security audit passes, I had a working XPI that did exactly what I wanted.

Now, Thunderbird is truly my own and does exactly what I need.

I'd like to thank the Thunderbird devs for making such good developer documentation for the app, for the APIs to write plugins, and for making the source code available under an open license. A good coding LLM (Claude Code, Codex, etc.) can probably make the plugin you need if one doesn't already exist.

That $50 I was going to spend on the eM Client upgrade is now going to Thunderbird as a donation when I get paid, and I'll probably set up a recurring annual donation.

Hi, I've been having a problem with Thunderbird for the past two days. The app keeps freezing and crashing. It doesn't matter if I'm in the middle of writing an email, adding an event to the calendar, or if the program is running in the background. I’ve already tried installing an earlier version (157.0), disabling my antivirus firewall (Eset Protect), and running Thunderbird in troubleshooting mode. Unfortunately, nothing helps.

https://www.thunderbird.net/en-US/thunderbird/158.0.1/releasenotes/
https://www.thunderbird.net/en-US/thunderbird/153.5.1esr/releasenotes/

This is very goofy !

I couldn't find a setting to change this behavior.

Hello, recently I noticed the From and Correspondents field is incorrect on about 10% of email in my Inbox. This is both for new as well as read mail.

I am running Version 153.5.0esr (32-bit) updated last week. I'm not sure if the issue pre-dates that version, but it's likely a new error (although I have seen older posts on the issue).

Repairing the inbox, and compacting it do not fix the issue.

TIA for any other advice.

<UPDATE> thanks u/sifferedd for the help. The fix was to check the setting for "Show only display name for people in my address book"

Email has been moved to a new server. Here's what we've done:

1. Copied profile to Dropbox.
2. Deleted email account from old server.
3. Created email account on new server - all settings are the same.
4. Tried to restore the backup according to these instructions but nothing happens.

ThunderNotes (https://github.com/flofrie/thundernotes) is a new plugin I created to scratch an age-old itch of wanting to make annotations for myelf in emails. Things like "This is done", "That's still TBD", "Task: do this next week!", or even just "called this person later, and he said it's not important".

Weirdly, it seems eMail clients don't usually offer that sort of stuff!

So, now we have Thundernotes. It's like sticking a post-it on a letter. Take notes, have them sync automatically and robustly to your other devices via IMAP (but no worries, all notes are stored there separately; it does NOT modify the actual emails an any way!), give them different colours, format them in Markdown; create tasks in notes, and see those in a powerful task overview (allows hashtags, date references, even regex filtering, if that's your thing).

I'm only just making it public, so I'd be grateful for bug reports and feature suggestions on Github. Despite the sub-zero version number I think it's pretty full featured, very stable and reliable, and just works really nicely.

Is it possible to create an "open settings" hotkey with tbkeys-lite (or some other addon)? If so, what would the code be?

I already wrote here how I started the Thunderbird Theme Creator, but I’ve made a lot of updates since then.

I've been working hard on tbthemes.com (https://www.tbthemes.com), a free website where you design your own theme

New ready-made themes

- Surprise me – makes a random theme with colours that go together

- From a picture – upload a screenshot of any mail app and it picks the colours for you (the picture never leaves your computer)

A much better preview

- See Mail, Compose, Calendar, Tasks and Contacts in the preview

Easier to use

- Undo / Redo (Ctrl+Z)

- Search box to find any setting

- Reset section to undo one part only

- Settings grouped with clear headings

-

…and many more

Lots of new things you can change

I'd love to hear your feedback...

UPDATE:

Thunderbird Theme Builder update: Evolve, colour-blind preview, share pictures and more....

New
- Evolve: see 6 variations of your theme
- See as: preview your theme the way colour-blind people
- Readability score with a "Fix it for me" button
- Share picture: save a nice picture of your theme to post anywhere.
…and many more

I'd like to present to you my Thunderbird extensions that enables you to browser your mails by contact.

Every modern messenger works this way: you pick a person and see your whole conversation with them. Contact Folders brings that to Thunderbird. The folder pane is replaced by a contact pane, and your mail is grouped by the people you write with, across all folders and accounts, including Sent and archives, or only for the one you have selected.

Try it out and give me feedback if you are interested. In my humble opinion this or something similar should be default in every mail program.

https://gitlab.com/gunwald/contact-folders

How it works

Contact Folders uses the contacts already in your address books. Pick a person, and you see everything you exchanged with them: their messages to you and your replies, threaded as conversations. It doesn't matter whether a message sits in the Inbox, an archive folder or Sent.

• Contacts are sorted by your most recent exchange, so the people you're talking to right now are always at the top. Unread badges show where new mail is waiting.
• The entry at the top shows all your mail at once, labelled with who it's from or who you wrote to.
• Mailing lists from your address book appear as groups, right among your contacts: like a chat, a group moves up when there's new mail and sinks when it's quiet. Selecting one shows the combined conversation with all members.
• Like a group chat: when you write with several people in one thread, they appear together as a group, even if you never saved them as a list. Everyone who took part in the thread belongs to it, blind copies excepted.
• New people, one click. Someone who isn't in your address book yet still gets an entry, whether they wrote to you or you wrote to them. Click + and Thunderbird's contact editor opens with their name and address filled in.
• Everything else stays Thunderbird. The message list, the reader, replying, filters, search and keyboard shortcuts are Thunderbird's own. The folder icon next to the search field (or the Contacts button in the toolbar) switches back to your folders at any time.

Perhaps I've missed it somewhere, but I cannot find the ability to add a delete button to the notification popup, or an extension that adds one. I occasionally did this from a different email client I have moved on from, to Thunderbird. I found it very helpful.

Can anybody help a fella out? Please...

Hi guys, running Thunderbird in Linux mint. Got it working but it's not seeing all of my imap folders. Server is outlook 365.

The subscribe thing does nothing, tried it both ways. Any other ideas?

Thank you!

Hi - could someone please advise if it is possible to fix the very unpleasant user experience with font-sizing in Thunderbird (on WIndows 11)? I'd really like to keep using this otherwise very convenient piece of sotware but I remember this issue from a long time ago and it doesn't appear to be improving with time.

Messages sent in GMail (via the browser) look normal in the browser. When opening them in Thunderbird, the letters are huge. Is this perhaps GMail's fault? Other emails show different anomalies - some have the text too large, some have it too small. Seems unlikely all those senders have their settings wrong.

I stumbled upon another thread here and tried toggling the setting for allowing (or not) incoming messages to choose their own fonts, changed the main and monospace font styles to 13 and 14, respectively (for both Latin and Cyrillic), with a minimum font size to 13 for both - but no luck with the GMail message text. Both sizes seem too large for my understanding, since I think Calibri at 11 is the most optimal one, but going below 14 for the Monospace turns a plain-text message too small to read. Is there some type of offset between normal font sizes (i.e. in Excel) and those in Thunderbird? Are there any more settings to change? Is this how everyone views their messages in Thunderbird? Surely this cannot be the case.

Thanks in advance for any useful replies.

I'm importing from Outlook and it says it's at 33%, but when I look at local folders I see content. And early on I did see it pulling in X of Y messages, but that status is now gone. I'm not sure if I should disrupt it by closing TB or just wait. It's been the better part of an hour, but there's no indication of how far along it is.

Every time I open Thunderbird, it returns to the same incorrect size and position. Every time I move it back and fix the size, and then the next time it's start all over. It will not accept any other position or retain it's window size. I have tried removing session and xulstore, which returns it to the defaults ONCE, I move it back to where it should be and resize it, and then it's right back to the same incorrect position and size again on the next start.

This is the only program on the entire windows computer that has or has ever had this issue. I do not understand what is going on. I have been posting about this for over a year with no effective solution.

New features in NovaBird-Extension (1.10.1), with matching changes in Search (1.2.8) and Conversation (0.15.2). DB, Send and the themes are the same as in 1.2.1 – install the new files over the old ones (same add-on IDs); settings are kept.

Colors and fonts

• New settings tab "Colors and fonts": with a NovaBird theme every main-window color can be changed (light and dark separately, each with a short description; a sketch of the window outlines the area a color affects). Only changed colors are stored, everything else keeps following the theme.
• Font sizes of the main window, compose window, settings pages and Nova-Contact in percent of the former size, with the resulting pixel size shown.
• Font sizes across Search, Conversation and Extension now follow Thunderbird's font setting (rem/em instead of fixed pixels). The compose window has one consistent base size and grows with Thunderbird's font size.
• AI summary (off by default)

"Summarise mail (AI)" - in the message header, and for a whole conversation in NovaBird-Conversation.
Works with Ollama on your own computer or an OpenAI-compatible service.

• Nothing is sent until you click, and only to the address you entered (a warning is shown when it is not on this computer). The instruction to the model is shown in the settings; it treats the mail as untrusted data, which reduces but cannot exclude prompt injection. Credentials are stored unencrypted in the add-on's profile data.
• Mailbox overview

Misc:

• New tab "Mailbox": folders, messages and size per account and in total, plus the largest folders. Read-only, from locally stored data.
• Compose window: new formatting bar (font list with live sample, size as a number, buttons of other add-ons move into it), lower header rows.
• Settings page of NovaBird-Extension reorganised: Message list · Colors and fonts · Right pane and attachments · Nova-Contact · Rules (beta) · AI · Mailbox; it reopens in the tab used last.
• Windows: the title block in the list header no longer leaves a wide gap before the search field; search field and time chips match the rest of the window.

More Info on NovaBird:

https://github.com/Novabird-Addons/NovaBird

https://github.com/Novabird-Addons/NovaBird/releases/tag/v1.3.0

Hey everyone!

I made a web app that lets you create your own Thunderbird themes without knowing any CSS. You can see your changes in a live preview and download your theme as an .xpi file when you're done.

Check it out: https://www.tbthemes.com

There's also a gallery where you can browse and download themes made by others, or use them as a starting point for your own.

Made something cool? You can publish it to the gallery and share it with everyone. When you publish, you get a secret edit key — save it, because that's the only way to edit or delete your theme later. No accounts, no sign-up.

How to install or update a theme

Thunderbird sometimes keeps using the old theme, even after you install a new version. To avoid this:

1. Open Add-ons and Themes (about:addons).

2. Remove the old theme.

3. Completely close Thunderbird.

4. Open Thunderbird again.

5. Click the gear icon → Install Add-on From File and select your new .xpi file.

Make sure you fully restart Thunderbird, or the old theme might still be used.

A quick note about testing

I mainly develop and test on KDE/Kubuntu 26 (Plasma, Wayland). I haven't tested it on Windows or macOS yet, so some things might look different, especially window buttons and spacing.

If you find any issues, let me know!

The app is completely free, requires no sign-up, and has no tracking. There's also a donate button if you'd like to support the project.

Feedback and suggestions are always welcome!

I've been using it for a year on my phone and want to use it on Windows. But I can't get used to the email list pane in card view at all.

• I really can't see a difference between read and unread emails - yes the text is a bit bolder, but it's not enough.
• I am missing the conversation view - with my sent emails showing as well.
• I am missing the cards buttons - there's only a star button, but I want more - delete, mark as unread, etc.

Can these be solved?

I just installed FluentBird which made it a bit nicer (those default toolbar icons, yikes), but cards themselves are still a struggle.

And on a side note, is there a way to have emails translated like in web gmail?

Hey everyone,

I know quite a few new Thunderbird themes have come out lately, and I love seeing that. Thunderbird is a really good mail client, the design was just always what kept me from using it.

So I built my own: a full redesign plus a small companion extension. I took the cleanliness of Apple Mail as the model, but wanted it to have its own character too, like the softly coloured spaces bar. It covers the whole app, not just the mail view, and the extension adds things like sender pictures, message previews and a merged address book. Dark mode works as well.

So far it's only tested on macOS.

Would anyone actually use something like this? If there's interest, I'd clean it up and publish it.

edit: it‘s now on Github: https://github.com/sruf79/halo-spaces/releases/latest - this is a very early alpha state, only tested on macos