Add-ons
Extensions by Weekly Downloads
Sort by:
Open Google Tasks (default)
Adds an icon on the spaces toolbar to quickly open the default Google Tasks page
Thunderbird Send
[IMPORTANT] This is a pre-release version Thunderbird Send. We will gradually open it for beta testing.
This add-on is built and maintained by your friends at Thunderbird.
Stay tuned to updates on thunderbird.net
copy-on-mouse-select
On Linux (Xorg / Wayland), selecting text with mouse or keyboard sends the selected text to PRIMARY selection.
This addon sends mouse selected text to regular clipboard.
See also https://addons.mozilla.org/fr/firefox/addon/copy-on-mouse-select/
New UNEC
New UNEC is a browser extension that transforms the UNEC student panel into a modern and user-friendly interface. It dynamically replaces the existing webpage’s HTML, CSS, and JS with an improved design, featuring automatic dark mode, language.
AI Email Assistant
Automatically generate email responses using AI through an external API integration. This add-on sends emails to an API and inserts the AI-generated response into your reply.
BulkDelete
Thunderbird MailExtension designed to help you efficiently bulk delete emails with multiple filtering options.
Custom Headers View
Display custom email headers in the mail header toolbar. This extension allows you to make visible specific headers in the toolbar, like received, date, DuckDuckGo's duck-original- headers to show the sender's email in the original format, etc.
Gemini Proofreader
This extension uses Gemini Flash 2.0 to proofread emails when the user clicks the extension icon.
Usage requires a Gemini API key. There is a free usage tier that should be more than adequate for almost every user.
OpenAI Proofreader
This extension uses OpenAI gpt-4o-mini to proofread emails when the user clicks the extension icon.
Usage requires an OpenAI API key. OpenAI does not offer a free usage tier. Proofreading a 4-5 paragraph email costs a fraction of a cent.
SpaceHey - Quick Access
Quick Access to SpaceHey in a new tab with just one click on a simple, stylish icon button on your Spaces toolbar.
Email Cleaner
Email Cleaner is an extension that allows you to delete emails from specific senders or specific subjects older than a certain number of days. The plugin is multilingual.
Interstellar Alliance Social Experiment Step 3
Send the Interstellar Alliance Social Experiment Step 3 letter as an email to a predefined online list of recipients.
TriliumClipper
A Thunderbird extension to clip messages and send them to the TriliumNext note taking application.
ThunderCalc
A simple calculator for Thunderbird/Sea Monkey/Firefox, available in a pop-up window or a separate tab.
Webbuttons - Google Messages Web
Adds a button in the toolbar for Google Messages Web. Icon source: https://www.flaticon.com/free-icon/comment_9449200
Webpage Print from Context Menu
ThunderSearch
Open a Google search browser window in Thunderbird from the context menu
Thunderbird-CloudLink
Inserting file link to mail with optional password and expiration date
Max Image WidthTo create your own collections, you must have a Mozilla Add-ons account.
