Add-ons
Extensions by Weekly Downloads
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Lightning
Requires Restart
Organize your schedule and life's important events in a calendar that's fully integrated with your Thunderbird email. Manage multiple calendars, create your daily to do list, invite friends to events, and subscribe to public calendars.
ImportExportTools
Requires Restart
Adds some tools to import and export folders and messages
Provider for Google Calendar
Requires Restart
Allows bidirectional access to Google Calendar
Enigmail
Featured
OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.
FlashGot Mass Downloader
Requires Restart
Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.
Auto Resize Image
Requires Restart
Resizer for inline and attachment images (JPEG, PNG, BMP and GIF image formats).
All platforms are supported (Windows, Linux and Macintosh).
CardBook
Requires Restart
Featured
A new Thunderbird address book based on the CardDAV and vCard standards.
Twitter: @CardBookAddon
Manually sort folders
Requires Restart
This extension allows you to manually sort (order) your folders in the folder pane of Thunderbird or automatically sort them, but in a better way. This extension also allows you to re-order accounts in the folder pane.
Saved Password Editor
Requires Restart
Adds the ability to create and edit entries in the password manager.
gContactSync
Requires Restart
Synchronizes contacts & groups between Thunderbird or SeaMonkey and Google Contacts. Imports Facebook friends, contacts you follow on Twitter, and more.
ExQuilla for Microsoft Exchange
Requires Restart
Thunderbird email accounts connecting to Microsoft Exchange Web Services.
Theme Font & Size Changer (fixed)
Fixed version (no 90 day timer till silent failure) of the popular "Theme Font & Size Changer for Thunderbird" addon
SQLite Manager
LookOut (fix version)
Requires Restart
LookOut is a plugin which allows Thunderbird to interface with Microsoft's mail tools by decoding metadata and attachments encapsulated/embedded in a TNEF encoded attachment (aka winmail.dat).
Support: Thunderbird and SeaMonkey
DKIM Verifier
Send Later
Requires Restart
True "Send Later" functionality to schedule the time for sending an email.
Quicktext
Requires Restart
Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.
LookOut
Requires Restart
LookOut is a plugin which allows Thunderbird to interface with Microsoft's mail tools by decoding metadata and attachments encapsulated/embedded in a TNEF encoded attachment (aka winmail.dat).
Password Exporter
This add-on allows you to export your saved passwords and disabled login hosts using XML or CSV files that can be imported later.
Note: This add-on won't work in Firefox 57. It may eventually if the APIs to access passwords are implemented.
To create your own collections, you must have a Mozilla Add-ons account.
