Up & Coming Extensions


True Full Screen in SeaMonkey No Restart

This extension enables true full screen mode in SeaMonkey for HTML5 video players, slide-shows, etc. and also for full screen invoked manually with the F11 key.

Rated 5 out of 5 stars (6)
1,061 users

Open With Photoshop No Restart

Open With Photoshop is a new companion for web and graphic designers to open up any web image with Adobe Photoshop via a single and quick mouse click.

Rated 5 out of 5 stars (46)
21,124 users

Stop Tube HTML5 No Restart

Stops autoplay of YouTube HTML5 videos (WebM). It is Flash-Block equivalent for HTML5 videos.

Rated 3 out of 5 stars (55)
10,976 users

HTTPS Everywhere

Encrypt the web! HTTPS Everywhere is a Firefox extension to protect your communications by enabling HTTPS encryption automatically on sites that are known to support it, even when you type URLs or follow links that omit the https: prefix.

Rated 4 out of 5 stars (31)
59,276 users


An input method editor (IME) for Vietnamese. Type Vietnamese diacritics directly into any Web page, Web app, or dialog box.
Bộ gõ tiếng Việt cho phép đặt dấu trực tiếp vào bất kỳ trang Web, ứng dụng Web, và hộp thoại.

Rated 5 out of 5 stars (30)
6,642 users

Add-ons Button No Restart

Opens the Add-ons window to perform tasks on your installed Extensions, Themes, Plug-ins and Language packs.

Rated 5 out of 5 stars (1)
1,221 users

uBlock Origin No Restart

Finally, an efficient blocker. Easy on CPU and memory.

Rated 5 out of 5 stars (229)
375,798 users


Join partial messages. Somewhat similar to MS Outlook Express "combine and decode".

Rated 5 out of 5 stars (2)
1,952 users


This wizard creates an XPI that rebrands Firefox, SeaMonkey or Thunderbird. You can change the brand name as well as the brand images and icons.

Rated 4 out of 5 stars (12)
1,338 users

InfoNotary Configurator for Mozilla

Configures Mozilla for work with certificates issued by InfoNotary Plc.

Rated 5 out of 5 stars (2)
11,749 users

Finnish spellchecker

Finnish open source Voikko-spellchecker for Mozilla and needed libraries.

Rated 4 out of 5 stars (96)
9,158 users

Close Proxy Authentication

Provides transparent proxy authentication on your enterprise network.
Close authentication dialog if login on proxy failed.

Rated 5 out of 5 stars (2)
2,134 users


Abilita la gestione alternativa degli allegati P7M

Not yet rated
1,712 users

RC Print

Adds a "Print" option to the Right-Click context menu.

Rated 5 out of 5 stars (2)
1,148 users

uMatrix No Restart

Point & click to forbid/allow any class of requests made by your browser. Use it to block scripts, iframes, ads, facebook, etc.

Rated 5 out of 5 stars (32)
10,630 users

Extension Options Menu

Adds extension options dialogs to the Tools or Titlebar menu and includes toolbar icon.

Rated 5 out of 5 stars (59)
6,940 users

LastPass Password Manager

LastPass, an award-winning password manager, saves your passwords and gives you secure access from every computer and mobile device.

Rated 4 out of 5 stars (1,237)
777,760 users

Quote Colors

Quote Colors allows you to select text and background colors of different quote levels which are applied when reading or printing mail/news messages. Additionally, you can choose between graphical and traditional plain text quoting display mode.

Rated 4 out of 5 stars (43)
15,418 users

Lightning Featured

Organize your schedule and life's important events in a calendar that's fully integrated with your Thunderbird email. Manage multiple calendars, create your daily to do list, invite friends to events, and subscribe to public calendars.

Rated 3 out of 5 stars (1,870)
5,876,075 users

Addressbooks Synchronizer

Synchronizes selected addressbooks with other instances of thunderbird
using ftp/webdav/imap servers

Rated 4 out of 5 stars (57)
38,743 users