Most Popular Extensions

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ImportExportTools NG

Adds tools to import/export messages and folders

EML, MBOX, HTML PDF , Plaintext Support and CSV support with indexes and file naming.

Rated 4 out of 5 stars (214)
237,831 users

Provider for Google Calendar

Allows bidirectional access to Google Calendar

Rated 3 out of 5 stars (1,652)
180,794 users

LookOut (fix version)

LookOut decodes winmail.dat (TNEF encoded) files that may come from a misconfigured Microsoft Exchange server or Outlook user allowing access to the original attachments
Support: Thunderbird

Rated 4 out of 5 stars (96)
161,551 users

Quicktext

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 (468)
120,119 users

Send Later

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

Rated 5 out of 5 stars (263)
97,430 users

Remove Duplicate Messages

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 (293)
91,088 users

TbSync

TbSync is a central user interface to manage cloud accounts and synchronize their contact, task and calendar information with Thunderbird.

Rated 5 out of 5 stars (255)
69,956 users

CardBook Featured

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

Twitter: @CardBookAddon

Rated 4 out of 5 stars (446)
65,549 users

Mail Merge

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

Rated 5 out of 5 stars (226)
63,777 users

Grammar and Spell Checker — LanguageTool

Check your emails for spelling and grammar issues

Rated 4 out of 5 stars (32)
58,749 users

Signature Switch

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

Rated 4 out of 5 stars (272)
51,134 users

FileLink Provider for Dropbox

Uploads your large attachments to your Dropbox instead of sending them by email. This uses Thunderbird's FileLink feature.

Rated 4 out of 5 stars (21)
49,290 users

Provider for CalDAV & CardDAV

This extension is no longer needed. Thunderbird has native CalDAV and CardDAV support.

Rated 5 out of 5 stars (54)
44,734 users

Owl for Exchange

Allows you to use your Exchange and Office365 email account with Thunderbird using Outlook Web Access (OWA).

Rated 5 out of 5 stars (195)
43,666 users

FileLink provider for WebDAV Featured

Uploads your large attachments to your WebDAV account instead of sending them by email.

Rated 3 out of 5 stars (22)
41,390 users

FileLink provider for Send

Securely encrypt and upload large attachments to any Send service instance (formerly Firefox Send).

Rated 5 out of 5 stars (17)
41,041 users

Web Translate

Web Translate is easy to use translator for your Web browser / Thunderbird!

Rated 4 out of 5 stars (24)
40,985 users

Minimize on Close

Causes Thunderbird's main window to minimize instead of closing. You can still close Thunderbird through the menu.

Rated 4 out of 5 stars (81)
37,242 users

Textmarker

Highlights selected text when composing emails. Default colour is yellow - other colours are available via Options.
(Works only during writing an e-mail, i.e. only in the compose window.)

Rated 5 out of 5 stars (32)
34,435 users

*cloud - FileLink for Nextcloud and ownCloud Featured

Upload large attachments to your Cloud and send the link by email

Rated 5 out of 5 stars (47)
31,265 users