Most Popular Extensions
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.
Provider for Google Calendar Requires Restart
Allows bidirectional access to Google Calendar
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.
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
ImportExportTools NG Requires Restart
Adds tools to import/export messages and folders (NextGen)
OpenPGP message encryption and authentication for Thunderbird.
Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.
Send Later Requires Restart
True "Send Later" functionality to schedule the time for sending an email.
gContactSync Requires Restart
Synchronizes contacts & groups between Thunderbird and Google Contacts.
Remove Duplicate Messages (Alternate) Requires Restart
Search and remove messages which are the same as other messages in your mail folders (referred to as duplicates or dupes).
CompactHeader Requires Restart
Add symbol in header plane to switch between compact and expanded view. Work only for Thunderbird 68.0 and older. Currently, there are no plans to update this for newer versions.
Signature Switch Requires Restart
Switch the signature on/off or choose a new one from your predefined set.
Create and Save or Send Multiple Individual and Personalized Messages from a Draft
CardBook Requires Restart Featured
A new Thunderbird address book based on the CardDAV and vCard standards.
ImportExportTools Requires Restart
Adds some tools to import and export folders and messages
TbSync Requires Restart
TbSync is a central user interface to manage cloud accounts and synchronize their contact, task and calendar information with Thunderbird.
Mail Redirect Requires Restart
Allow to redirect (a.k.a. "remail") mail messages to other recipients.
Confirm-Address Requires Restart
Confirm E-mail address before sending mail
Allows you to use your Exchange email accounts that use Outlook Web Access (OWA) with Thunderbird
Addressbooks Synchronizer Requires Restart
Synchronizes selected addressbooks with other instances of thunderbird
using ftp/webdav/imap servers