1. ImportExportTools

It’s a given that you’ll want to freely import and export emails from your Thunderbird client; to convert invoices into PDFs, for example, or to import a saved profile to instantly organize your email how you like. ImportExportTools lets you do these things, and many, many more (indexing messages of a folder in HTML format for example, or export messages as single files in many common formats). An essential addition.

2. Classic Toolbar Buttons

Has Thunderbird been progressing a little too fast for you, and you just want a bit of it at least to remind you of the good old days? Classic Toolbars is here to help, letting you replace the fancy new UI elements of Firefox with ones dating back to the earliest versions of Thunderbird. It’s a purely cosmetic thing, but you spend a lot of time looking at your email client so you may as well make it look how you want.

3. Lightning

A calendar is one of the most important tools for anyone in business. You need to be able to quickly look and access your day. Needing to have multiple windows open and toggle back and forth is very inconvenient. Lightning is Mozilla’s calendar application. This extension lets you add a full calendar to Thunderbird, making it more efficient to schedule appointments from an email. Some users have complained that this addon tends to stop working with major Thunderbird updates, and subsequently needs updating, but the following addon has a good workaround to that…

4. Provider for Google Calendar

So you know that thing we said about Lightning breaking down with Thunderbird updates, and people losing their vital calendar information? Provider solves that problem by syncing up with your Google Calendar, so whatever you write into Lightning gets saved to your Google Calendar and vice versa. This ensures that even if Lightning does fail on you, you still have access to your calendar information.

5. Enigmail

Keeping your email information secure and private is as vital as ever. Thunderbird doesn’t come with any encryption features built into it, so you should get Enigmail as quickly as possible. This addon, recommended by Mozilla itself, lets you encrypt messages using GnuPG, a fork of the widely used OpenPGP encryption standard. It’s nice and easy to use, and keeps track of your encryption keys in a handy Key Management window.

6. QuickFolders

Calling itself the “Swiss army knife” of folders, QuickFolders turns the messy folders and subfolders within Thunderbird into sharp-looking tabs running across the top of your screen (yes, just like tabs in a web browser). It’s particularly handy if you have important info buried deep in a sub-folder somewhere that you want to access more easily.

7. Mail Redirect

Not quite the same as forwarding, Mail Redirect redirects emails sent to you so they appear to the recipient like emails received directly from the original sender. This is particularly useful in work environments where emails may get sent to the wrong person/department and you want the right person (or people) to get them.

8. Stop Ignoring Reply:To

Sorry, no pictures for this one, as it’s basically a backend addon! A simple but a good one. As of Thunderbird 52, when you replied to an email that had a different “reply-to” email address from the original sender’s, Thunderbird would ignore it and send emails back to the original sender instead (defeating the whole point of the “reply to” box and probably resulting in your reply not getting read). Stop Ignoring solves this hiccup in Thunderbird, and ensures that if there is a “reply-to” option, that your emails will reply to that and not the original sender. Excellent.

9. Reminderfox

When you get busy working or playing on Facebook, you might not notice it is time for the meeting. Reminderfox is a popular Firefox browser extension that is also available in Thunderbird. If you are trying to have an all-in-one mail application, reminders and to-do lists will help a lot.

10. Send Later

As the name implies, you gain the ability to schedule emails with Send Later. I use the schedule feature for a ton for things like birthdays, follow up etc. When you type up an email and it is ready to send, you can go to “File -> Send Later” or use the keyboard shortcut to bring up the Send later window. From this window you can choose a preset time or choose sometime more specific.

11. Nostalgy

If you process a large number of emails everyday, Nostalgy will save you a lot of time. This add-on will let you create keyboard shortcuts for actions like move a message to a folder or change folders.

12. Themes

Last but not least are themes for Thunderbird. If you spend a lot of time using your email program, it may as well be visually appealing, right? You can choose from over 70 different themes to spruce up your inbox. While many people will not use any add-ons for Thunderbird. It is a fantastic program right out of the box so to speak. However, using one or more of the add-ons will only extend its usefulness.

Conclusion

There’s plenty for you to pick from here, but there’s a whole lot more out there on the internet. These are the things that we deemed essential to a swift, secure Thunderbird experience, though obviously every user’s needs are different. What are the Thunderbird addons that you simply can’t live without? Let us know in the comments! This article was first published on Jan 2011 and was updated in Jan 2018