Message Composition

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Send Later

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

Rated 5 out of 5 stars (45)
62,797 users

Mail Merge Featured

Mass Mail and Personal Mail

Rated 5 out of 5 stars (141)
55,635 users

Clippings

Save frequently-entered text for pasting later.

Rated 4 out of 5 stars (178)
42,992 users

Stationery

Extension to mimic Outlook Express Stationery.
Allow you to use HTML files as templates for mail. Also allow custom template in replies or forwarded mail!

Rated 4 out of 5 stars (108)
38,883 users

Check and Send

Check the message contents and addresses before you send the message...

Rated 4 out of 5 stars (29)
21,606 users

SmartTemplate4

SmartTemplate4 offers an easy way to automatically create customized replies by auto-inserting various mail headers. Templates can be created for every account as well as for the default (all email accounts). Also supports the Stationery Add-on.

Rated 5 out of 5 stars (49)
18,918 users

ThunderPEC

ThunderPEC semplifica la gestione della Posta Elettronica Certificata (PEC) e delle comunicazioni PCT e FatturaPA in Thunderbird.

Rated 5 out of 5 stars (12)
16,028 users

Highlighter

Quickly highlight some text in Thunderbird message composing windows.

Rated 4 out of 5 stars (50)
9,532 users

Markdown Here

Write your email in Markdown, then make it pretty.

Rated 4 out of 5 stars (18)
8,209 users

Toggle Word Wrap

Toggle word wrapping and PRE element wrapping in the message composition and HTML display windows, respectively.

Rated 4 out of 5 stars (38)
6,786 users

Transliterator No Restart

As-you-type phonetic conversion of text from one alphabet to another, as well as transliteration/detransliteration of selected text anywhere within documents. Supports multiple languages and custom transliteration schemes.

Rated 5 out of 5 stars (77)
6,728 users

Flex Confirm Mail

Confirm mail address and attachments based on flexible rules.

Rated 1 out of 5 stars (1)
6,219 users

Extra Format Buttons

Adds a font size (in pixels), strikethough, subscript and superscript buttons to Thunderbird's Compose Window.

Rated 5 out of 5 stars (6)
4,931 users

Email signature for Thunderbird - WiseStamp

Switch Thunderbird email signatures. Supports Gmail, Yahoo, AOL & Outlook webmails. Youtube, Facebook, Twitter icons & more

Rated 4 out of 5 stars (2)
4,090 users

BorderColors GT

How many time you sent an email from your wrong email address?
This add-ons allows you assign a different color to the compose window border for each of your email addresses. So you can immediately view from what account are you writing.

Rated 4 out of 5 stars (8)
3,972 users

SmilieInserter Plus

Insert smilies in messages.

Rated 5 out of 5 stars (17)
3,725 users

AVIM

Vietnamese-language input method editor (IME). Type diacritics directly into any Web page, Web app, or dialog box. Convenient, comprehensive, secure.
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Bộ gõ tiếng Việt cho phép đặt dấu trực tiếp vào bất kỳ trang Web, ứng dụng Web, hộp thoại.

Rated 5 out of 5 stars (31)
3,569 users

Emoji Menu

Adds the ability to easily insert emojis into your composed messages in Thunderbird.

Rated 4 out of 5 stars (3)
3,259 users

Automatic Dictionary No Restart

Remembers the language you use with a person or group of people, and switches the spellchecker language automatically for you next time. You do not have to do it manually any more. It remembers and switches it for you.

Rated 5 out of 5 stars (21)
2,838 users

CategoryManager

Category manager for CardDav contacts, also allows to send an email to all members of a category (categories can be used as contact groups).

Rated 5 out of 5 stars (9)
2,448 users