If you use Mozilla’s Firefox browser, you are probably familiar with Themes and Extensions, which are add-ons that let you add new features, change the way your browser behaves, or modify the way your browser appears. With thousands of add-ons available, the sky is pretty much the limit when it comes to browser customization.

In 2015, Mozilla announced that it would move away from the current Extensions platform toward WebExtensions, and in 2016, Mozilla announced that WebExtensions would be the only way to add functionality or change the behavior of your browser by the end of 2017. The official date for this transition is when Firefox 57 ships.

Add-on Extensions vs. WebExtensions

Mozilla’s move to its WebExtensions platform is designed to:

  • Make it easier to develop cross-browser extensions: the goal is to make it easy to write extensions that run without any (or minimal) modifications on any major browser, and the WebExtensions framework is very similar to the one used to develop browser extensions for Opera and Google’s Chrome.
  • Increase stability by making it less likely that changes to Firefox break an add-on: currently, extensions are highly intertwined with the Firefox system, so updates to the browser itself often broken extensions. Vendors provided fixes, but until the patches could be shipped, users were left with broken extensions. One of the goals for WebExtensions is to remove this dependence on the browser to minimize issues as a result of upgrades and updates to Firefox.
  • Be easier to maintain: in a way, this is an extension of the explanation above. If your extension is not breaking due to browser upgrades/ updates, you will not have to fix them. But the framework with which WebExtensions is built on is more defined and separated from the browser itself.

Why WebExtensions?

The specifics between current themes/extensions and WebExtensions are technical in nature, but here is a very simplified explanation.

Currently, developers are able to touch almost anything in the browser’s code, which means that they can implement some very powerful add-ons. However, the converse of this is that developers can also do things that impact a user’s browser very badly (albeit accidentally). As explained above, the tight coupling between the browser and the add-on meant that upgrades and updates to the browser itself frequently broken extensions.

Mozilla’s answer to these downsides is the WebExtension, which you can think of as being similar to a set of building blocks. Add-ons cannot rely on anything used for the browser and can only be built with the blocks provided by Mozilla. This decoupling of add-ons from the browser means that add-ons can no longer wreak havoc on users’ browsers, either deliberately or accidentally.

What the Switch to WebExtensions Means for You

In the end, what you should know is that once Firefox 57 ships, any extension that is not a WebExtension (or theme that is incompatible with the WebExtension platform) will not load when Firefox launches. If you want to retain the functionality and behavior of your browser as it is, you will need to install the WebExtension equivalents of your existing themes and extensions.

Add-Ons in Firefox 57

To that end, this article will list the WebExtension equivalents for some of the most commonly used add-ons. In some cases, there are already plans to convert an extension to a WebExtension. If an extension is dead and there are no plans for someone to develop a WebExtension equivalent, we do not list the extension. Once Firefox 57 ships, you cannot even use legacy extensions, even if they are already installed.

Installing New Add-Ons

If you are looking to install new add-ons, consider opting for only those that have been tagged as compatible so that you do not have to update when Firefox 57 ships.

How to Find Add-Ons That are Compatible with Firefox 57+

All extensions and themes, as well as collections, which are curated groups of add-ons around a specific theme, such as Privacy Matters, Password Managers, and Dynamic Media Downloaders, can be found on the add-ons page on the Mozilla website.

Currently, there is no way to search or filter for extensions that are compatible with Firefox 57+. We assume that this is because Firefox 57 is currently unavailable, and in the future, you will not be able to install non-compatible extensions. For the time being, when you are browsing search results lists or category groupings, you can identify WebExtensions by looking for a green tag next to the extension name that says COMPATIBLE WITH FIREFOX 57+.

uBlock Origin Compatible with Firefox 57


If the extension is not compatible with Firefox 57, the download button will be grayed out like this:

Incompatible with Firefox 57

A Note on Themes

Currently, Firefox supports two types of themes: Complete and Lightweight.

  • Complete Themes are those that completely replace the default Firefox appearance. Developers of complete themes must provide all CSS, images, and icons for the browser. This means that developers have a lot of control, but the themes themselves are difficult to create and difficult to maintain given how tightly intertwined they are with the browser itself.
  • Lightweight Themes, which are the more popular option, are much simpler to create; anyone can create one simply by uploading an image.

With the release of Firefox 57, Mozilla is hoping to blend the ease of creating a Lightweight Theme with the functionality most often seen in Complete Themes. Essentially, developers will create a manifest that “layers” changes on top of the default Firefox theme. The Mozilla team will also be adding a WebExtensions API for theming, so changes to themes can be done at runtime.

What this means is that Complete Themes won’t work once Firefox 57 launches, and there really won’t be an alternative. Lightweight Themes, however, can easily be ported (if they haven’t been already).

Alternatives to the Most Popular Add-Ons

AddBlock for Firefox

The following is a list of the most popular extensions for use with Firefox, as well as its current compatibility with Firefox 57+. If it is not compatible, we have provided the best possible alternatives for you to consider.

  1. Adblock Plus (ABP): Using the existing Adblock Plus for Chrome codebase as a starting point, the Adblock Plus team is working to close the existing feature gap (as compared to the current version offered for Firefox users). The AdBlock Plus team will offer this tool as a WebExtension beginning fall 2017. There is also a less feature-rich version from the same developers called Adblock for Firefox, which is already available.
  2. uBlock Origin: Already compatible with Firefox 57+. No updates are necessary.
  3. Video DownloadHelper: If you are using Video DownloadHelper to improve the download speed of your videos, consider using something like Internet Download Manager. If you are using this extension for its media grabbing features, consider installing Bulk Media Downloader, or Video Downloader Prime.
  4. Easy Screenshot: Easy Screenshot is designed to a web page. Other screenshot-related tools with similar functionality that you might consider include Nimbus Screen Capture or Awesome Screenshot Plus.
  5. NoScript Security Suite: NoScript has released a hybrid WebExtension, and it has a full WebExtension in development. Once Firefox 57 ships, you’ll automatically be migrated to the NoScript WebExtension.
  6. Firebug: In 2017, Firebug, a powerful web development tool, functionality was merged into the built-in Firefox Developer Tools. You can use the Dev Tools without installing any add-ons.
  7. Cisco WebEx Extension: Already compatible with Firefox 57+. No updates are necessary.
  8. Ghostery: Already compatible with Firefox 57+. No updates are necessary.
  9. DownThemAll!: For downloading media, consider Bulk Media Downloader, Video Downloader Prime, or 1-Click Downloader. If you want something that downloads links, movies, and audio clips on a given page with just one click, keep your eye out on FlashGot Mass Downloader; the WebExtension version is in development. Finally, there are also Multiple File Downloader and Download Master.
  10. Greasemonkey: The current stable version of Greasemonkey is not compatible with Firefox 57, but the development team plans to launch version 4, which will work with Firefox 57. If you are interested in moving to this version before Firefox forces you to switch, you can download an alpha test version. You might also consider using Violentmonkey or Tampermonkey.

Alternatives to Your Favorite Add-Ons

The following add-ons aren’t among the top 10, but many users find them useful. Since they will not work once WebExtensions become the norm for add-ons, here are alternatives that you might consider using instead.

Privacy and Security

These add-ons give Firefox a security boost, or offer other security advantages like malware detection.

  1. Browser-SecurityBitdefender TrafficLight for Firefox can be used instead of Browser-Security to protect yourself against malware and phishing attacks.
  2. CrazyMailing’s Disposable Temporary E-Mail Address: Generate and use a temporary email address to protect yourself from spam and to stay anonymous using Bloody Vikings! or Temp Mail – Disposable Temporary Email.
  3. Disconnect: Ported and already compatible with Firefox 57+, so you can continue seeing the invisible sites that are tracking you and block them.
  4. Flashblock: To prevent yourself from seeing anymore Flash animations, you can use a fork of Flashblock called Flash Block (Plus).
  5. FoxyProxy Standard: A port for this proxy is in the works.
  6. HTTPS EverywhereSmart HTTPS can help you force all your web traffic to use the more secure HTTPS protocol.
  7. LastPass Password ManagerBitwarden is a free password manager that, as a bonus, also works on other devices, such as smartphones and tablets. 1Password is a stand-alone program that offers a WebExtension that you might be interested in using.
  8. Private Tab: Use Incognito This Tab to open the current tab in an incognito tab.

Content and Media

Facebook Unfriend Finder

Control media, and monitor social networking activity, with these alternative WebExtensions.

  1. Download YouTube Videos as MP4 has two alternatives: YouTube Download & Adblocker Smarttube and YouTube Video and Audio Downloader.
  2. Enable WhatsApp Web: WhatsApp Web is already fully compatible with Firefox, so you don’t need any add-ons to use it.
  3. If you are a fan of Facebook, you are in luck. The world’s largest social media network seems to get a lot of love from add-on developers, and the following Facebook-related WebExtensions are ready to go:
  4. Feedly – Beyond Google Reader: Feedly, which rose to prominence with the demise of Google Reader, has functionality that can easily be duplicated by Reader or Awesome RSS.
  5. Instagram already has a lot of WebExtensions for use with its product, including web-based Instagram, Instagram Video Download, and Image Download for Instagram.
  6. Lucifox No known WebExtensions support viewing content in OPDS format yet. But if you need just the ability to read .epub ebooks within the browser, you can use EPUBReader.
  7. Simple RSS Reader (SRR): Alternatives to Simple RSS Reader include Reader and Awesome RSS.
  8. TwitterfoxShare on Twitter allows you to share the content you find on the web to your Twitter feed. Twitter as a Sidebar lets you use Twitter in a sidebar within your browser.
  9. YouTube Enhancer Plus – If you use YouTube Enhancer Plus, you might consider:


These handy add-ons have not yet been converted to WebExtensions, but we’ve made recommendations for alternatives.

  1. Gmail Notifier: An alternative version, Gmail Notifier + is compatible with Firefox 57. If you would like to try something new, consider Checker Plus for Gmail or Panel & Notifier for Gmail.
  2. Google Docs Viewer (PDF, DOCX, PPTX, XLSX, etc…): An alternate tool for viewing documents in your browser is Docs Online Viewer.
  3. Google Translator for Firefox: If you want to translate full web pages, try Dictionary (Google Translate) Anywhere; if you are working more frequently with snippets of text, use Page Translator (though Page Translator does work with full pages of text as well).
  4. iMacros for Firefox: iMacros automates a lot of tasks, including filling out forms, downloading files and extracting data, and so on. There isn’t a WebExtension out there that duplicates all its functionality, but you can get assistance with web forms from AutoFill Forms or AutoFormer+.
  5. Open with Photoshop:  You can send content for use in Photoshop with Edit with Adobe Photoshop.
  6. Print Edit: To print things off the internet without the extras, such as whitespace or advertisements, consider Print Friendly & PDF or Print Edit WE.
  7. TodoFox: To manage your to-do lists and reminders, you can use Todo or TickTock instead of TodoFox.
  8. Webmail Ad Blocker, which removes ads from web-based email accounts, has already been ported and will function once Firefox 57 is live.
  9. X-notifier: If you are using a web-based email account, you can continue to get notifications using X-notifier, which will be ported to WebExtensions.


Forecastfox WebExtension

Quickly replace dead utility add-ons with new WebExtensions that offer similar functionality.

  1. FlagfoxCountry Flag+ displays a country flag based on the server location of the active tab’s URL. You might also consider Country Flags & IP Whois or Active Whois & Flags extension.
  2. Forecastfox Weather: To continue using this product, which gets international weather forecasts from AccuWeather.com and displays them in any toolbar or status bar, grab the WebExtension version the developers have released. If you’d like another weather-related WebExtension, consider Gismeteo.
  3. Google Reverse Image Search: Other ways to perform reverse image searches include TinEye Reverse Image Search or Reverse Image Search.
  4. Image Block prevents images from downloading, which is helpful when you are browsing on a slower connection. You can get the same functionality from Image Video Block.
  5. Open Bookmarks in New Tab: The Open Bookmarks in New Tab add-on will no longer be needed, since its functionality will be built in to Firefox 57.
  6. QuickDrag: Alternatives to QuickDrag include Glitter Drag.
  7. Random Agent Spoofer: This extension is in the process of being forked. In the meantime, you might consider uMatrix.
  8. ScrollyFox: Alternatives to ScrollyFox include Scroll to Top, Shift + Scroll (Horizontal Scrolling), or Scroll++.
  9. Tab Mix Plus: Tab Management, which is where you change the way opening and closing tabs behave, is an area where there are already multiple WebExtensions available already, including New Tab Override, New Tab Tweaker, Custom New Tabs, Change New Tab, and newtab.urlEX.
  10. Theme Font & Size Changer: Currently, there’s no alternative to this app since theme-related changes (and the ability to make them) are in flux, but a temporary fix might be changing the zoom of your browser window with Zoom Page WE.
  11. TinyURL Generator – Create shortened URLs with 1-Click Shorten URL.


By the end of 2017, Mozilla will have released Firefox 57, which means that non-WebExtensions add-ons will no longer function with your installation of Firefox. Given the features and functionality added by the assorted add-ons available, this proves to be problematic for many people.

However, developers are aware of the changes to come, and many, especially those who are responsible for the most popular extensions, are rolling out WebExtensions versions of their products. Some are available today, while others are porting their products from the Chrome versions they have already developed. Unfortunately, not all existing extensions have viable alternatives, and this article sought to find WebExtensions (or WebExtensions to be) whose functionality is similar, if not identical, to those of the original product.