Message Composition

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Clippings Requires Restart

Save frequently-entered text for pasting later.

Rated 4 out of 5 stars (199)
5,185 weekly downloads

Auto Resize Image Requires Restart

Resizer for inline and attachment images (JPEG, PNG, BMP and GIF image formats).
All platforms are supported (Windows, Linux and Macintosh).

Rated 4 out of 5 stars (25)
4,653 weekly downloads

Mail Merge Requires Restart Featured

Mass Mail and Personal Mail

Rated 5 out of 5 stars (149)
2,541 weekly downloads

Send Later Requires Restart

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

Rated 5 out of 5 stars (103)
2,466 weekly downloads

Signature Switch Requires Restart

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

Rated 4 out of 5 stars (189)
1,353 weekly downloads

MEGAbird Requires Restart

Add MEGA support to Thunderbird's Filelink feature.

Rated 5 out of 5 stars (8)
1,020 weekly downloads

Emoji Requires Restart

Add emojis to your e-mails.

Rated 5 out of 5 stars (7)
769 weekly downloads

Check and Send Requires Restart

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

Rated 4 out of 5 stars (30)
700 weekly downloads

Stationery Requires Restart

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 (104)
687 weekly downloads

ThunderPEC Requires Restart

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

Rated 5 out of 5 stars (11)
640 weekly downloads

SmartTemplate4 Requires Restart

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 (50)
512 weekly downloads

AVIM Requires Restart

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 (34)
352 weekly downloads

Emoji Menu Requires Restart

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

Rated 4 out of 5 stars (7)
310 weekly downloads

Markdown Here Requires Restart

Write your email in Markdown, then make it pretty. NOTE: This is the legacy XUL version, for Thunderbird, Postbox, Pale Moon, etc. *Not* for modern Firefox; for that use this: https://addons.mozilla.org/en-US/firefox/addon/markdown-here/

Rated 5 out of 5 stars (30)
292 weekly downloads

Transliterator

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 (75)
278 weekly downloads

Automatic Dictionary

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 (29)
242 weekly downloads

Nextcloud for Filelink Requires Restart

"Nextcloud for Filelink" is an Open Source Thunderbird extension which makes it easy to send large attachments with Thunderbird by uploading them first to a Nextcloud server and by then inserting the link into the body of your email.

Rated 3 out of 5 stars (23)
239 weekly downloads

ThunderHTMLedit Requires Restart

Thunderbird HTML editor. This add-on adds a HTML tab to the composition window where you can see and edit the HTML source of the message.

Rated 5 out of 5 stars (5)
227 weekly downloads

CategoryManager 2 Requires Restart

Category manager for Thunderbird 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 (8)
195 weekly downloads

Highlighter Requires Restart

Quickly highlight some text in Thunderbird message composing windows.

Rated 4 out of 5 stars (48)
179 weekly downloads