Most Popular Extensions
privateID Requires Restart
This extension displays a warning if you send a message from your private emailID to an address/ mailing list which is not found in your Personal Address Book...
Provides button to copy the list of current reminders to the clipboard.
DictsInfo Requires Restart
Search the highlighted text at Dicts.info.
Message Notes Requires Restart
Add Notes to messages. Notes are stored in a plaintext file, typically in your profile. The plaintext notes file can be stored elsewhere to enable sharing of notes across a...
Edit HTML Source Requires Restart
You can now edit the HTML source in the Compose...
EuropeanMX Spam Reporter Requires Restart
Train your EuropeanMX filter by reporting unrecognized spam or false-positives back to us.
Mark Read On Reply Requires Restart
A simple extension to mark messages read after you click a reply menu or button (or Ctrl+R)
PONG! Multiplayer Requires Restart
Play a game of PONG! while you are waiting.
World Weather Requires Restart
Display local weather information from around the...
PasteIP Requires Restart
Easy pasting of your IP address or User-Agent in a textbox. Comes in handy when posting on forums, etc.
Lowercase Email Addresses in Message Headers Requires Restart
Shows lowercase email addresses in message headers and their tooltips.
Resubmit Requires Restart
(Re)submit multiple messages to a predefined recipient(s)
After Unsent Mail Is Sent Requires Restart
Run a program of your choice after unsent mail has been sent.
Soapy Requires Restart
Bypasses DNS-based censorship
NOTE: This was created as a SOPA protest in 2012. This does not work anymore for most sites. Use Tor instead.
FlatStyle for Thunderbird Requires Restart
This gives you a style similar to MS Office XP in your Thunderbird menus and toolbars, and Calendar as well if you have that installed. It also changes the category-selector in the options window to use your system colors, instead of always being...
Limit_Offline_Message_Size Button Requires Restart
Limit the size of a message to download with a single click of the button for slow (and/or expensive) network connection.
Quick access to Tools->Account Settings->Disc Space->"To save disk space, do not download: Messages larger than XXkB"
Markov Dictionary Switcher Requires Restart
Based on Dictionary Switcher but more than a thousand times faster and you can choose dictionaries that you want to use. Detects the language of the message that you are composing and changes the spelling dictionary.
Mail Sent Notifier Requires Restart
Allows to notify a HTTP-GET based webservice after successfully sent an email, e.g. for time registration systems.
Nightly Tester Tools Lite Requires Restart
This is a cut down version of Nightly Tester Tools by Mossop, which is 77.6 KB. I've only included the "copy build id" and "build id in titlebar"...