Add-ons
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).
Send Later
Requires Restart
True "Send Later" functionality to schedule the time for sending an email.
Signature Switch
Requires Restart
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
Requires Restart
Check the message contents and addresses before you send the message...
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.
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.
Send Later Button
Requires Restart
A simple button to invoke the (already existing) send later functions.
Flex Confirm Mail
Requires Restart
Confirm mail address and attachments based on flexible rules.
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.
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.
Markdown Here
Requires Restart
Write your email in Markdown, then make it pretty.
CategoryManager
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).
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.
Grammar CheckerTo create your own collections, you must have a Mozilla Add-ons account.
