Message Composition



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)
17,787 users

SmilieInserter Plus

Insert smilies in messages.

Rated 5 out of 5 stars (17)
3,566 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 (76)
7,099 users

Send Later

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

Rated 5 out of 5 stars (39)
57,364 users

Mail Merge Featured

Mass Mail and Personal Mail

Rated 5 out of 5 stars (134)
50,332 users

Address Widget Lines

Address Widget Lines provides the ability to select the number of address lines to display in the message compose window.

Rated 5 out of 5 stars (18)
681 users

Markdown Here

Write your email in Markdown, then make it pretty.

Rated 5 out of 5 stars (15)
6,436 users

Automatic Dictionary No Restart

Extension that remembers the language of the spellchecker used when composing and switches to it every time you write to that person.

Rated 5 out of 5 stars (20)
2,560 users


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

Rated 5 out of 5 stars (30)
6,277 users


Save frequently-entered text for pasting later.

Rated 4 out of 5 stars (166)
33,948 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 (5)
3,990 users

Color Text Compose Buttons

Adds Text Color Buttons in Compose Toolbar and More: Pixel FontSize, Strikethough, Sub & Superscript, Lower & UpperCase. Also provide Tools: Insert iframe, Launch MathType, Maths & Greek Symbols, Load Template Variables and Duplicate Compose Window.

Rated 5 out of 5 stars (15)
1,848 users


Easily and quickly to encrypt / decrypt
For users: private messages via e-mail, blogs, social networks, forums, etc.
For webmasters: websites, images, photos, etc.
Support: Firefox, Thunderbird and SeaMonkey

Rated 5 out of 5 stars (6)
1,276 users


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 (6)
1,316 users

Check and Send

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

Rated 4 out of 5 stars (25)
24,753 users

Send and Archive

Adds a button to send an email and archive the original message.

Rated 5 out of 5 stars (8)
371 users


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 (107)
38,729 users


Save your email into Evernote by forwarding it to Evernote email address.
Before you use it, you need to specify your Evernote email address (see the screenshot).

This function can be invoked by "Forward to Evernote" in the context menu.

Rated 5 out of 5 stars (5)
2,242 users

DL for Thunderbird

Allows to convert large attachments to links automatically without 3rd party providers.

Rated 5 out of 5 stars (3)
1,468 users

Flexible Identity

Selects an identity based on the recipients list when sending an email

Rated 4 out of 5 stars (23)
1,656 users