Message Composition

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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 (61)
5,136 weekly downloads

Mail Merge

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

Rated 5 out of 5 stars (230)
2,236 weekly downloads

Send Later

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

Rated 5 out of 5 stars (264)
2,002 weekly downloads

Signature Switch

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

Rated 4 out of 5 stars (273)
802 weekly downloads

MEGAbird Requires Restart

Add MEGA support to Thunderbird's Filelink feature.

Rated 4 out of 5 stars (42)
727 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 (168)
574 weekly downloads

ThunderPEC Requires Restart

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

Rated 4 out of 5 stars (38)
495 weekly downloads

Emoji

Add emojis to your e-mails.

Rated 4 out of 5 stars (64)
488 weekly downloads

Check and Send

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

Rated 4 out of 5 stars (49)
455 weekly downloads

SmartTemplates Featured

SmartTemplates offers an easy and powerful way to automatically create customized replies by auto-inserting various mail headers. Templates can be created for every mail identity, Stationery files can now be imported and used directly.

Rated 4 out of 5 stars (80)
414 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 (49)
306 weekly downloads

FlexConfirmMail

Confirm mail address and attachments based on flexible rules.

(This project was renamed from "Flex Confirm Mail" to "FlexConfirmMail", due to a branding reason.)

Rated 4 out of 5 stars (11)
243 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 (45)
231 weekly downloads

Markdown Here Requires Restart

Write your email in Markdown, then make it pretty.

Rated 4 out of 5 stars (46)
184 weekly downloads

CategoryManager

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 (25)
183 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 (16)
179 weekly downloads

Shrunked Image Resizer

Make your photos smaller, so they don't take forever to email.

*Shrunked Image Resizer is no longer maintained.*

Rated 4 out of 5 stars (88)
170 weekly downloads

ReplyWithHeader

Outlook style headers and few goodies for Thunderbird.

Rated 5 out of 5 stars (93)
162 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 (94)
145 weekly downloads

Identity Chooser

Identity Chooser helps you to always use the correct identity when composing a new email.

Rated 4 out of 5 stars (147)
135 weekly downloads