Add-ons for Firefox (en-US)

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Dictionary Anywhere

Double-click any word to instantly see its definition.

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Extensions are like apps for Firefox.

They add features to Firefox to make browsing faster, safer, or just plain fun.

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Tab managers

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Privacy & Security extensions

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Productivity extensions

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Recommended extensions

Block Site
A customizable, password-protected website blocker and redirector.
Rated 4 out of 5
Ray
72,423 users
Measure-it
Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.
Rated 4.4 out of 5
Trishul
26,474 users
Web Archives
View archived and cached versions of web pages on various search engines, such as the Wayback Machine and Archive․is.
Rated 4.7 out of 5
Armin Sebastian
62,809 users
Print Edit WE
Edit the contents of a web page prior to printing or saving. Elements in the web page can be edited, formatted, hidden or deleted. Unwanted content, such as adverts and sidebars, can easily be removed.
Rated 4.1 out of 5
DW-dev
39,858 users

YouTube customization

AdBlocker for YouTube™
Remove all annoying ads from YouTube.
Rated 4 out of 5
AdblockLite
549,127 users
SponsorBlock - Skip Sponsorships on YouTube
Easily skip YouTube video sponsors. When you visit a YouTube video, the extension will check the database for reported sponsors and automatically skip known sponsors. You can also report sponsors in videos. Other browsers: https://sponsor.ajay.app
Rated 4.8 out of 5
Ajay (SponsorBlock)
525,136 users
Enhancer for YouTube™
Take control of YouTube and boost your user experience!
Rated 4.7 out of 5
Maxime RF
610,853 users
YouTube NonStop
Tired of getting that "Video paused. Continue watching?" confirmation dialog? This extension autoclicks it, so you can listen to your favorite music uninterrupted. Working on YouTube and YouTube Music!
Rated 4.2 out of 5
lawfx
136,753 users

Tab managers

Tree Style Tab
Show tabs like a tree.
Rated 4.5 out of 5
Piro (piro_or)
232,457 users
Simple Tab Groups
Create, modify, and quickly change tab groups
Rated 4 out of 5
Drive4ik
93,065 users
OneTab
OneTab - Too many tabs? Convert tabs to a list and reduce browser memory
Rated 4.2 out of 5
OneTab Team
167,564 users
Tabliss - New Tab
A beautiful New Tab page with many customisable backgrounds and widgets that does not require any permissions.
Rated 4.6 out of 5
tabliss.io
76,153 users

Popular themes

Activist – Balanced
Rated 4.7 out of 5
Mozilla Firefox
657,261 users
Visionary – Balanced
Rated 4.6 out of 5
Mozilla Firefox
425,484 users
Dreamer – Balanced
Rated 4.8 out of 5
Mozilla Firefox
371,708 users

Accessibility extensions

Dark Reader
Dark mode for every website. Take care of your eyes, use dark theme for night and daily browsing.
Rated 4.5 out of 5
Dark Reader Ltd
1,223,325 users
Zoom Page WE
Zoom web pages (either per-site or per-tab) using full-page zoom, text-only zoom and minimum font size. Fit-to-width zooming can be applied to pages automatically. Fit-to-window scaling can be applied to small images.
Rated 3.8 out of 5
DW-dev
28,286 users
Read Aloud: A Text to Speech Voice Reader
Read out loud the current web-page article with one click. Supports 40+ languages.
Rated 3.8 out of 5
LSD Software
171,879 users
Sidebery
Vertical tabs tree and bookmarks in sidebar with advanced containers configuration, grouping and many other features.
Rated 4.7 out of 5
mbnuqw
77,149 users

“mp3” tagged extensions

Easy Youtube Video Downloader Express
A simple extension for superfast and easy YouTube downloads in FLV, 3GP, MP3, MP4, 720p, and 1080p formats.
Rated 4.2 out of 5
Dishita
567,130 users
600% Sound Volume
Up to 600% volume boost
Rated 4.5 out of 5
Aliaksandr
164,936 users
Global Speed
Set a default speed for video and audio.
Rated 4.7 out of 5
POLYWOCK
69,342 users
YouTube mp3
The YouTube-mp3 Add-on generates a "MP3" button on YouTube. Convert YouTube to mp3 and download the file to your device.
Rated 3.5 out of 5
Addon Developer
35,177 users