Thunderbird Blog

Thunderbird lives in an entity called MZLA, created by Mozilla and the Thunderbird Council (the elected open source community leadership) to be the legal and financial home to Thunderbird. MZLA, which I lead, receives only money via donations from donors. We are a for-profit because the IRS is very skeptical of nonprofits who develop FOSS software (someone down below linked to a bunch of great links on this topic). We, do, however publish tons of information on what we are doing on our blog, and we are open source and a community run project, so if you really want to go deep on this - come join us in making Thunderbird. Great links: https://blog.thunderbird.net https://www.thunderbird.net/en-US/participate/

It's mostly already available, just not the default: https://blog.thunderbird.net/2023/08/make-thunderbird-yours-how-to-get… I followed the steps in that blog post and was able to mostly get there. I have a bit less padding between folders than the mock-up showed (which seems like a theme thing rather than a configuration item), and I don't have profile pictures in the message list.

They are keeping both: "Quite a few people seem to love K-9 Mail and have asked us to keep the robot dog around. We believe it should be relatively little effort to build two apps from one code base. The apps would be virtually identical and only differ in app name, app icon, and the color scheme. So our current plan is to keep K-9 Mail around." https://blog.thunderbird.net/2023/12/when-will-thunderbird-for-android…

Did you know that Thunderbird has RSS support? https://blog.thunderbird.net/2022/05/thunderbird-rss-feeds-guide-favor… I use it for a news site in my country primarily and it's cool to have a list that's not full of pictures and ads and other distracting things, but just simple article headers that I can open and read if interested. Feeds are precious due to that alone, even. Also, here's some of the blogs that HN users run: https://hn-blogs.kronis.dev/ I wonder if there's gonna be another blog sharing thread sometime, whoever had the original idea was pretty cool.

Sorta! It's no longer a Mozilla Corporation product, although it's still owned by the Mozilla Foundation (it spun off as MZLA). But that being said, yes, I agree! (Thunderbird isn't great, though, and there's no iPhone version. I'd much rather be able to, for example, use Superhuman or Spark or something. Right now, I give Google all my data, and don't even use the GMail interface.) Source: https://blog.thunderbird.net/2020/01/thunderbirds-new-home/

So much negativity in this thread, jeez. I love current Thunderbird but it undeniably has its issues. Firstly, of course this is subjective, but its UI is starting to look dated. Lots of you are complaining about modern UIs, but I think the designs [0][1] look great and are much more readable than the current design, which looks straight out of Ubuntu 8.04. Then there are some major UX issues, the most obvious one being the lack of conversation view, which is how pretty much everybody expects an email client to work in 2023. Supernova implementing that is reason enough to be excited about the release. I can't wait to try it out - keep up the awesome work, team! [0] https://developer.thunderbird.net/planning/roadmap [1] https://blog.thunderbird.net/2022/11/thunderbird-supernova-preview-the…

Thunderbird operates independently within Mozilla: > There was a time when Thunderbird’s future was uncertain, and it was unclear what was going to happen to the project after it was decided Mozilla Corporation would no longer support it. But in recent years donations from Thunderbird users have allowed the project to grow and flourish organically within the Mozilla Foundation. Now, to ensure future operational success, following months of planning, we are forging a new path forward. Moving to MZLA Technologies Corporation will not only allow the Thunderbird project more flexibility and agility, but will also allow us to explore offering our users products and services that were not possible under the Mozilla Foundation https://blog.thunderbird.net/2020/01/thunderbirds-new-home/

On 2, I actually think that the right sideproject does have the ability to market Firefox and grows its userbase better than making incremental gains in the browser. For example, Firefox Send was a clever way of putting the brand in front of many people who might never have seen it. On 3, I too would love to see that happen, but, from the outside at least, the project has seen so much upheaval [1]. I don't really understand the significance of the latest change, at the start of the year [2], but hopefully it's a good sign. [1] https://en.wikipedia.org/wiki/Mozilla_Thunderbird#History [2] https://blog.thunderbird.net/2020/01/thunderbirds-new-home/

I did back in February, but I'm unlikely to be able to completely accurately recount that now. One thing I do remember is Ryan explaining how just being willing to directly ask people for money has been surprisingly effective. It's also worth putting Thunderbird's relationship to Mozilla in proper perspective: for all intents and purposes, Thunderbird is a completely independent project. Since 2017 (https://blog.thunderbird.net/2017/05/thunderbirds-future-home/), the Mozilla Foundation has primarily acted as Thunderbird's fiscal home, providing support for donations / bookkeeping / taxes / legal matters much in the same way that the Software Freedom Conservancy hosts Git, Homebrew, Inkscape and others, or how Software in the Public Interest hosts PostgreSQL, systemd, Xorg, FFmpeg, 0 A.D, and more. If I understand last year's MZLA Technologies announcement correctly (https://blog.thunderbird.net/2020/01/thunderbirds-new-home/), it sounds similar to the split between the Mozilla Foundation and the Mozilla Corporation, where the former is a legal non-profit and the latter entity is for-profit and able to enter into commercial, revenue-generating agreements, but still wholly owned by the non-profit Foundation. ...But you should really listen to the podcast, I could be getting all of this wildly wrong.

> Mozilla started transitioning Thunderbird out of their umbrella while TB is still highly dependent on Firefox code. If you are referring to Mozilla Messaging and the period to 2012, no the only transitioning was in terms of product functionality. The community organized in 2014, unaffiliated with Mozilla, and it's not until about 2018 when staff were hired that community leadership were able to seriously reduce technical debt. But seriously reducing dependency on Firefox code is some distance away. > Maybe we need a successor to Thunderbird? Something that's not tied to Firefox so much? You are looking a millions of dollars paid developer time. > Because it seems like we can't trust Mozilla and however many unpaid/underpaid volunteers to maintain it well enough. Mozilla are not running the show here, the community is. Perhaps it's difficult to keep up with the history, but https://blog.thunderbird.net/ has past relevant postings, plus developer and other mailing lists. To cite a couple, big changes in encryption https://blog.thunderbird.net/2019/10/thunderbird-enigmail-and-openpgp/ https://mail.mozilla.org/pipermail/tb-planning/2019-December/007286.ht… and development priorities http://lists.thunderbird.net/pipermail/maildev_lists.thunderbird.net/2… which includes a new address book. There is a significant professional development staff which is nicely paid, and the number of developers will soon double.…

> https://blog.thunderbird.net/files/2026/07/post-screenshot-06-month-vi… Just another reminder what people who designs these things do not use them. Probably at all. Useless left bar - eating space, useless top bar - eating much more limited vertical space, stupid arrows in BL corner without meaning or sense, stupid hamburger menu on the top right corner - because if you don't move the cursor a lot means you are not actually working.

At one of last Blender conferences, the founder (and at that time CEO) gave some insights about funding and compared it to Thunderbird. https://youtu.be/VZ5022VaMmA?si=m1hD9wEQ16s8Zu3b&t=1297 ; Fore More recent numbers: In 2024[1] (last info I found), Blender had 3.1m € in donations (600k more than the year before) and Thunderbird had around 9m € [2]. I kind of get it, Blender is way more niche than Thunderbird, but imagine what they could do with even more money. [1] https://download.blender.org/foundation/Blender-Foundation-Annual-Repo… on page 76 [2] https://blog.thunderbird.net/2025/10/state-of-the-bird-2024-25/ I did the money conversion based on today's exchange rates

Thunderbird has actually come back to Mozilla around 2017: https://blog.thunderbird.net/2017/05/thunderbirds-future-home/ And has been operating as a fully fledged subsidiary of the foundation since 2020: https://blog.thunderbird.net/2020/01/thunderbirds-new-home/

Apparently, they did a rework of the interface a few years ago. https://github.com/thunderbird/developer-docs/blob/master/thunderbird-… and https://blog.thunderbird.net/2023/02/the-future-of-thunderbird-why-wer…

Thunderbird currently runs entirely on donations, even though they have paid products in the pipeline. I think a piece of software running on donations is not running off "charity". It's just a business model to not charge every user. Similar to how Twitch streamers operate, or my local theater group. You can read how they spent money in 2024 [1]. [1] https://blog.thunderbird.net/2025/10/state-of-the-bird-2024-25/

Mostly to "technical staff" who work on product and infrastructure. I just don't think the point of the donate page was to be an information warehouse but instead just a dead simple donate page. The other info is googleable if you're looking for it. https://blog.thunderbird.net/2025/10/state-of-the-bird-2024-25/

They are an entity separate from Mozilla: * https://blog.thunderbird.net/2020/01/thunderbirds-new-home/

The most recent report/breakdown I see: https://blog.thunderbird.net/2025/10/state-of-the-bird-2024-25/

Not that it answers your question, but the move happened in 2020 to "hire more easily, act more swiftly, and pursue ideas that were previously not possible". https://blog.thunderbird.net/2020/01/thunderbirds-new-home/

I'm not an heavy o365 user but i'm almost happy on Debian KDE with thunderbird 148[0] (email only), teams-for-linux[1] (chat/calendar/whatever), Onedrive[2] and webdav (sharepoint)[3]. Libreoffice/Onlyoffice for documents. [0] https://blog.thunderbird.net/2025/11/thunderbird-adds-native-microsoft… [1] https://github.com/IsmaelMartinez/teams-for-linux [2] https://github.com/abraunegg/onedrive + https://github.com/bpozdena/OneDriveGUI [3] Store the SP cookie via konqueror visiting the SP site, then open it in dolphin via "webdavs://CORP.sharepoint.com/sites/SITE/Shared Documents/" (sometimes the cookie is very short-lived)

Thunderbird has been re-added to the products steered by the Mozilla Foundation. https://blog.thunderbird.net/2023/11/the-untold-history-of-thunderbird…

Source: https://blog.thunderbird.net/2025/12/thunderbird-2025-review-building-…

Yeap. It's mentioned in their financial reports that user donations represent more than 99.9% of our annual revenue[0]. Also seems their staff is mainly engineers/developers, and all the expenses are concentrated to their product*. Thunderbird doing what Firefox should. [0]: https://blog.thunderbird.net/2023/05/thunderbird-is-thriving-our-2022-… *Though Thunderbird is Gecko-based so can be said in part, perhaps a significant one, they're depending on Firefox development.

Thunderbird is entirely funded by donations for some years now and is more than enough. In 2024, Thunderbird received $10.3M (19% increase over the previous year) in donations which was used to employ 43 people. https://blog.thunderbird.net/2025/10/state-of-the-bird-2024-25/

Read the docs? https://blog.thunderbird.net/2025/11/thunderbird-adds-native-microsoft…

We implemented this in the Daily build of the desktop app last year, using a staging environment for Firefox Sync. But Firefox Sync is called Firefox Sync because it’s built for Firefox. Thunderbird profiles, in comparison, have a lot more data points. This meant we had to build something completely different. As we started to spin up Thunderbird Pro, we decided it made more sense to have a Thunderbird account that would manage everything, including Sync. Unfortunately, this meant a lot of delays. So Sync is still on our radar, and we hope to have it next year, barring further complications. Source: https://blog.thunderbird.net/2025/09/state-of-the-thunder-mozilla-conn… In other words, it was more work to adapt Firefox Sync than they thought at the beginning. It's still actively developed so finger crossed it's coming soon.

Good luck to them! On a nother note: still 1+ year(s) until we get a real email database (enabling gmail like thread view) in TB. [0] [0] https://blog.thunderbird.net/2025/10/video-conversation-view/

They wrote about this recently. With "Panorama" [1] they want to introduce an SQLite DB for all messages that will also be responsible for the search index. [1] https://blog.thunderbird.net/2025/10/video-conversation-view/

The support is only for the EWS protocol (MS Graph will probably come next year). You can enable it in beta by going to Config Editor (this is primarily for advanced users), searching for the preference "experimental.mail.ews.enabled" and setting it to true. You would have to manually add the account. Currently only mail is supported. No calendar support. See https://blog.thunderbird.net/2025/07/thunderbird-monthly-development-d…

Yes! My pet peeve is people keep saying "no one would pay" or "it wouldn't work" but the thing is, as far as I know, it has never been tried. For example Thunderbird is fully funded by donations.[1] Of course Thunderbird's budget is in a different magnitude than Firefox but I'd guess the amount of users is also in a different magnitude. [1] https://blog.thunderbird.net/2023/05/thunderbird-is-thriving-our-2022-…