Add-ons
Message Composition
Sort by:
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).
Mail Merge
Create and Save or Send Multiple Individual and Personalized Messages from a Draft
Send Later
True "Send Later" functionality to schedule the time for sending an email.
Signature Switch
Switch the signature on/off or choose a new one from your predefined set.
MEGAbird
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!
ThunderPEC
Requires Restart
ThunderPEC semplifica la gestione della Posta Elettronica Certificata (PEC) e delle comunicazioni PCT e FatturaPA in Thunderbird.
Emoji
Check and Send
Check the message contents and addresses before you send the message...
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.
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.
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.)
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.
Markdown Here
Requires Restart
Write your email in Markdown, then make it pretty.
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).
Emoji Menu
Requires Restart
Adds the ability to easily insert emojis into your composed messages in Thunderbird.
Shrunked Image Resizer
Make your photos smaller, so they don't take forever to email.
*Shrunked Image Resizer is no longer maintained.*
ReplyWithHeader
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.
Identity Chooser
Identity Chooser helps you to always use the correct identity when composing a new email.
To create your own collections, you must have a Mozilla Add-ons account.
