Add-ons
Message Composition
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Send Later
Grammar and Spell Checker — LanguageTool
Check your emails for spelling and grammar issues
Mail Merge
Create and Save or Send Multiple Individual and Personalized Messages from a Draft
Signature Switch
Switch the signature on/off or choose a new one from your predefined set.
FileLink Provider for Dropbox
Uploads your large attachments to your Dropbox instead of sending them by email. This uses Thunderbird's FileLink feature.
FileLink provider for Send
Securely encrypt and upload large attachments to any Send service instance (formerly Firefox Send).
Owl for Exchange
Allows you to use your Exchange and Office365 email account with Thunderbird using Outlook Web Access (OWA).
Textmarker
Highlights selected text when composing emails. Default colour is yellow - other colours are available via Options.
(Works only during writing an e-mail, i.e. only in the compose window.)
*cloud - FileLink for Nextcloud and ownCloud
Featured
Upload large attachments to your Cloud and send the link by email
Emoji
FlexConfirmMail Stable
Confirm mail address and attachments based on flexible rules.
This is enterprise edition with less updates. Another edition for regular users:
https://addons.thunderbird.net/thunderbird/addon/flex-confirm-mail/
Shrunked Image Resizer
Make your photos smaller, so they don't take forever to email.
*Shrunked Image Resizer is no longer maintained.*
FileLink Provider for Box
Uploads your large attachments to your Box instead of sending them by email.
ReplyWithHeader
Simple Mail Redirection
Allows you to resend (also known as redirect) email messages.
Uses 'cardbook' if installed
Bases on the add-on 'Mail Redirect' by Onno Ekker and Pawel Krzesniak
Please see the support page on how to use and why it sometimes does not work!
BorderColors D
Shows a colorful border around the "New Message" window, so you can tell different identities apart.
Builds on the original BorderColors and the "GT" version, adding different border styles.
Identity Chooser
Identity Chooser helps you to always use the correct identity when composing a new email.
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).
Attach from ClipboardTo create your own collections, you must have a Mozilla Add-ons account.
