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 (236)
244,250 users

Provider for Google Calendar

Provider for Google Calendar connects Thunderbird with Google Calendar for full task sync, conference details, and scheduling support. It offers deeper integration than Thunderbird’s native support using Google’s official API.

Rated 3 out of 5 stars (1,725)
159,781 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 (101)
155,302 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 (496)
107,465 users

Send Later

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

Rated 5 out of 5 stars (267)
105,688 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 (312)
90,764 users

Mail Merge

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

Rated 5 out of 5 stars (236)
67,115 users

Grammar and Spell Checker — LanguageTool

Check your emails for spelling and grammar issues

Rated 4 out of 5 stars (39)
65,563 users

CardBook Featured

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

Twitter: @CardBookAddon

Rated 4 out of 5 stars (490)
60,045 users

TbSync

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

Rated 4 out of 5 stars (271)
49,470 users

Signature Switch

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

Rated 4 out of 5 stars (310)
48,908 users

Web Translate

The best Translator for Thunderbird!

Supported translators:
Google Translate
Microsoft Translator
DeepL
Yandex
Яндекс Переводчик
Google 翻译
百度翻译

Rated 4 out of 5 stars (35)
48,043 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 (24)
47,362 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)
45,075 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 (213)
43,149 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 (23)
40,765 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 (99)
39,138 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 (36)
37,810 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 (54)
34,038 users

Provider for Exchange ActiveSync

Add sync support for Exchange ActiveSync (EAS v2.5 & v14.0) accounts to TbSync

Rated 4 out of 5 stars (63)
25,742 users