Most Popular Extensions

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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.

Rated 3 out of 5 stars (2,021)
7,401,570 users

ImportExportTools Requires Restart

Adds some tools to import and export folders and messages

Rated 4 out of 5 stars (229)
440,476 users

Provider for Google Calendar Requires Restart

Allows bidirectional access to Google Calendar

Rated 4 out of 5 stars (1,131)
305,359 users

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.

Rated 4 out of 5 stars (365)
189,243 users

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

Rated 4 out of 5 stars (43)
146,670 users

Enigmail Requires Restart

OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.

Rated 4 out of 5 stars (242)
118,098 users

Quicktext Requires Restart

Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.

Rated 4 out of 5 stars (358)
107,544 users

gContactSync Requires Restart

Synchronizes contacts & groups between Thunderbird and Google Contacts.

Rated 4 out of 5 stars (291)
89,467 users

CompactHeader Requires Restart

Add symbol in header plane to switch between compact and expanded view. New beta versions for the current beta of Thunderbird 68.0 can be found at https://github.com/jmozmoz/compactheader/

Rated 5 out of 5 stars (175)
83,843 users

Send Later Requires Restart Featured

True "Send Later" functionality to schedule the time for sending an email.

Rated 5 out of 5 stars (155)
81,787 users

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).

Rated 4 out of 5 stars (203)
81,158 users

Signature Switch Requires Restart Featured

Switch the signature on/off or choose a new one from your predefined set.

Rated 4 out of 5 stars (207)
66,931 users

Mail Merge Requires Restart

Create and Save or Send Multiple Individual and Personalized Messages from a Draft

Rated 5 out of 5 stars (178)
66,082 users

CardBook Requires Restart

A new Thunderbird address book based on the CardDAV and vCard standards.

Twitter: @CardBookAddon

Rated 4 out of 5 stars (226)
52,485 users

Mail Redirect Requires Restart

Allow to redirect (a.k.a. "remail") mail messages to other recipients.

Rated 4 out of 5 stars (131)
39,857 users

ImportExportTools NG Requires Restart Featured

Adds tools to import/export messages and folders (NextGen)

Rated 4 out of 5 stars (24)
38,588 users

Addressbooks Synchronizer Requires Restart

Synchronizes selected addressbooks with other instances of thunderbird
using ftp/webdav/imap servers

Rated 4 out of 5 stars (63)
36,022 users

PrintingTools Requires Restart

Adds some options to print messages and addressbooks

Rated 5 out of 5 stars (33)
31,268 users

Display Quota Requires Restart

This extension will display the current status of your IMAP quota in thunderbird's statusbar and will warn you when you reach a configurable limit...

Rated 4 out of 5 stars (38)
31,267 users

Confirm-Address Requires Restart

Confirm E-mail address before sending mail

Rated 5 out of 5 stars (55)
30,702 users