Keeping Tabs on the Tab API

tabsTabs are central to the modern browsing experience, so much so that it is hard to imagine that we once browsed the Internet without them, one single window at a time. Now, it’s common to have several tabs open at once — perhaps one playing music, several with online articles you want to read later (pro tip: check out Pocket for this use case), and of course, a few tabs with whatever you are supposed to be working on at the moment.

The Past

From the start, Firefox extensions that dealt with tabs were a natural fit and have proven to be quite popular. The good news is that there are already hundreds of extensions written with the WebExtensions API to help you configure, organize and otherwise manage your browser tabs. You can arrange your tabs as tiles or in a tree, put them on the side of the browser, or control where new tabs open, just to name a few.

Unfortunately, not every feature that was available in the past can be offered using the WebExtensions API. Several of the most popular tab extensions under the legacy add-on system used the unrestricted nature of that environment to offer powerful and unique features. Along with that power, however, came security risks. The WebExtensions API seeks to temper those risks by providing limited access to browser internals.

The Future

We’re working to support additional tab features, but how we achieve this goal will be shaped by our dedication to Web standards, the speed and stability of Firefox, our product vision, and especially our commitment to security and privacy and the principles of the Manifesto. It’s clear that some previously available tab features will not be available under the WebExtensions API; they just can’t be accommodated without potentially compromising user security or privacy.

However, we believe many other features can be added. Providing as much tab-related functionality as we can within these constraints is a high priority. Starting with tab hiding, you can expect to see additional functions added to the WebExtensions API over the next several releases that will allow developers to create rich, compelling extensions to style, manage and organize browser tabs.

All of this, of course, will be part of our push for open Web standards. However, while that process proceeds at its own pace, don’t expect to see us stand still. Using feedback from developers, we will continue to innovate within the WebExtensions API, providing new ways to surprise and delight users. As always, thank you for using Firefox and helping ensure that individuals have the ability to shape the Internet and their own experiences on it.

32 comments on “Keeping Tabs on the Tab API”

  1. Jim Kirk wrote on

    “Tabs are central to the modern browsing experience, so much so that it is hard to imagine that before Firefox we browsed the Internet without them”

    Hang on, NetCaptor and Opera had tabbed browsing before Firefox existed. Credit where credit is due.

    1. Mike Conca wrote on

      You are absolutely correct, Jim, I should have done a bit more homework on this. It seems most people point back to NetCaptor as the original tabbed browser, although there are some other versions of the history out there as well. We’re not going to settle that here, so I edited the post to remove any browser reference. Thanks again.

  2. Revertron wrote on

    Please, give us possibility to hide close buttons on tabs and close them by doubleclick 🙁

    1. Mike Conca wrote on

      Thanks for your feedback, Revertron. Closing tabs via double-click is a potential feature we’ll consider to enhance the WebExtensions API for tabs.

      1. Grzegorz wrote on

        If you can, please make this generic. Personally I use double clicking on a tab to open a new tab next to it and middle clicking to duplicate a tab. (Tab Mix Plus allows that.)

        For closing I use either ctrl+w or close buttons, except close buttons only appear when you hover over the tab. This proved to be really unintrusive and intuitive – my non-technical friends and family didn’t even notice the buttons were hiding, but once I pointed it out to them they admitted it’s pretty nice. It allows you to see more of the tab’s title and makes the browser look cleaner.

        And big thanks for your work on modernizing Firefox. I hope various WebExtension APIs will appear quickly so I can move from 52 ESR to the amazing 57 and beyond. 🙂

        1. john wrote on

          i, personally, would like a Double-click to reload tab

        2. Bill wrote on

          Whats possibility of eventually letting us MOVE entire Tab row to below URL bar. Like to have tabs on top of web site. Need be able to use the old Classic Theme Restorer type of add on, lots of options, but at lest be able to move Tab bar. Also sort of like Vivaldi, ability to move Bookmark sidebar to either Left or Right side

  3. Fx0 wrote on

    This comment should be deleted. It’s a troll comment and the user is offending.

  4. Graham Perrin wrote on

    > … hundreds of extensions written with the WebExtensions …

    With the new look AMO, that link does not yet allow visitors to browse what’s required. There’s prominence to legacy extensions, blockers for bitcoin mining, and so on.

    Please see (2017-10-28)

    Also, from

    > … mis-placement of an extension in a category … when misplacements significantly increase the information overload, there’s a sense of being spammed by AMO. …

    Really, too much of what’s categorised as tabs-related is not tabs-related

    1. Mike Conca wrote on


      Thanks for the feedback. The rollout of the new AMO design was coincident with my blog post. The AMO team has seen the discourse threads you pointed to in your post and is working hard to improve things.

      1. Graham Perrin wrote on

        Cool. Thanks.

        For now I guess that (twelve extensions) is a good starting point. Probably better than browsing hundreds 🙂

        1. Michael Hagerty wrote on

          I was surprised, make that shocked, when I opened Firefox 57 and saw that all of the tab extensions I had been using the day before had been relegated to Legacy, i.e., Tab Mix Plus, Tab Groups Manager, Tab Groups Helper and Session Manager.

          My machines have very fast CPUs, 16GB of RAM and an SSD as their primary disks. Since the machines have the power, I chose to have 75+ tabs distributed over seven Tab Groups. Firefox gave me all of the sites I wanted to see as soon as it had opened – any sloth was unnoticable. I use bookmarks for odd, infrequently used sites; what is used frequently I expect to have right there in front of me, two clicks at most; no need to go looking in a bookmark list, as I want them handy.

          I gather that the developers of the add-ons may put together versions using the new API in the fullness of time. Until then, Firefox moves into third place as my favorite browser. The other two never had this power, so I don’t expect them to as good as pre-v57. I am hoping that when the replacement versions appear, the new versions will be able to ingest the saved files from v56. I have a great fear that the developers of Firefox 57 may have deleted those files in the update, figuring, “Hey, we don’t support these extensions, so we might as well just delete all of those saved configuration files and start afresh. Who could possibly want all those extension-specific files laying around?” Yes, I have seen that level of chutzpah in the past from Microsoft and other companies, so the fear remains.

          Short of opening Firefox every day to see if there is an equivalent extension for the legacy ones, is there any other way to check? BTW, the “recommended replacements” lists for these tab-enhancing add-ons is laughable.

      2. Graham Perrin wrote on

        An alternative link, for a view of hundreds:

        – although things such as ‘Print Edit WE’ are miscategorised.

  5. RS wrote on

    What do web standards have to do with the tab extension APIs? It’s Firefox’s business, and Firefox’s alone.

    If you disagree with this, you’re basically telling all your users “hey guys, we’d love to let you do this thing with Tabs, but, uh, Chrome can’t do it, so I’m afraid we can’t do it either”.

    1. Mike Conca wrote on

      When I referred to web standards, it was in the context of setting those standards more than staying within existing ones. Firefox can, and will, offer WebExtension API that are not part of any standard. Our goal is to empower developers with a rich API so that they can, in turn, offer users the best possible Internet browsing experience. Some of these API may only make sense for Firefox, but others, we hope, will be adopted by different browsers and eventually become part of the browser extension standard.

      For example, the current draft of the browser extension standard can be found here:

      However, Firefox already offers WebExtension API that go beyond that standard, such as Contextual Identities and Find, two extension features not currently found in any other browser.

  6. Graham Perrin wrote on

    In an earlier comment I posted the wrong cross reference. Sorry.

    Instead, with an embedded YouTube video of the problem:

  7. Donna wrote on

    I am hoping that Tabs on the Bottom will be available. It is easier, quicker and neater to have them on the bottom. My opinion anyway!

    1. truth wrote on

      I wholeheartedly agree. Never understood why they changed the tab bar’s location to be above the location bar. Seems very counter-intuitive considering the user will have their cursor below that area 90% of the time. It’s one of the reasons I’ve stuck to using CTR for as long as I have and I’ll continue to have my layout this way. The only thing I’m getting bumbed about is the bookmarks toolbar’s placement in Nightly. Of course, being Nightly, it isn’t for sure what’s to come. However, I haven’t been able to put the bookmarks toolbar below the location bar since a couple updates ago. I seriously hope that don’t commit to that and let us move it where we want. It currently won’t let me move it below the location bar but will allow it above it and somehow allows merging with the tabs bar, which is unnecessary.

      1. Deadly-Bagel wrote on

        Firefox updated on my computer this morning and CTR is no longer compatible, as far as I’ve found there appears to be no replacement.

        You can utilise the userChrome.css file to move the tabs to the bottom but the bookmarks are then still above the Address Bar, while I prefer to have them below it but above the tabs.

        Found out how to move the Bookmarks below the address bar, but it puts it below the tabs as well… Come on Firefox, you’re supposed to be the browser leading in customisation but then you lock everything in place and break the addons that fix it.

  8. Basil wrote on

    important question, will we ever be able to have this hot mess:

    look and do the same thing that this add on is able to do?

    Because the creator keeps whining that they’re not going to be able to replicate the old functionality. So I wanna know who I yell at, you, or them.

    1. Grzegorz wrote on

      Out of curiosity: what do you use it for? (I’m just a random guy, not from Mozilla.)

  9. Stacy wrote on

    I have used Firefox for a number of years, and I donate periodically. I also have used Roboform for about 15 years. It’s hard to get use to not have the Roboform bar at the top. Any future plans to change that?

    1. Mike Conca wrote on

      Roboform just updated their extensions on AMO. Check it out and see if it meets your needs.

  10. Daisy wrote on

    Firefox update has disabled universal print add on. I am looking for an add on where I am able to print all the open tabs at the same time. Does anyone know of an equivalent add on I have had no luck finding it.

    1. Caitlin Neiman wrote on

      Hi Daisy, I just checked and wasn’t able to find a 1:1 equivalent for Universal Print. 🙁 You might want to ask about this in our community forum to see if anyone can recommend a good replacement.

  11. Andy R wrote on

    As a guide, tab mix plus contained loads of great features.

    Please – either incorporate them into the Core UI options, or make your WebExtensions API support them.

    In General, I can see why you might want to limit ehat is out of the box for Firefox, but please wherever possible create an API with loads of options. It can’t hurt to allow someone who is particular enough to download an extension the choice they want.

  12. Scavenger wrote on

    Frankly, the loss of tab rows will pretty much drive me away from Firefox.
    A single line scrolling off screen breaks the entire visual language of tabs. Why it wasn’t built in to Firefox rather than relying on plug ins like Tab Mix made no sense anyhow, but breaking it…

    As for “security”, there’s no such thing. All activities have calculated risks. Put in a check box saying that this add-on lowers the “security” of the browser at your own risk and get on with business.

  13. rex thompson wrote on

    I SHALL avoid Quantum until the last possible moment! It destroys my browsing ways without offering the usual extentions,etc that MADE firefox the best browser! EASY to use, intuitive! i hope your other users get you to quickly bring “mew” firefox up to date, and NOT gaudy/messy/gosh aint this great?please revert to a reasonable update, thank you rex thompson

  14. Dwayne wrote on

    what?! no session manager or tab mix plus support? firefox quantum is a disaster in my book if these 2 extensions arent supported in the new version. firefox has been my go-to browser for decades bcz of this very fact: its extension support. and now you take that away from me, i might as well use ms edge.

    1. Robert Ab wrote on

      I agree. Session Manager is also crucial addon for me.

  15. Ian wrote on

    Longtime FF fan but still in shock at the loss of tab mix plus in 57. You can create the fastest, most secure browser but, without the basic useability enabled by TMP, it’s a waste. I’m hanging onto 56 for a bit but will go to Chrome unless this gets a quick fix.

  16. Marcus wrote on

    Dear Mozilla Team,

    pleeease, please make it possible for Add-Ons again to detect clicks on the active tab, and mouse-wheel click and mouse-wheel turning inside the tab bar!

    This would enable the most powerful yet “smallest” features like: send active tab to back by re-clicking it (a.k.a. tab-flipping), and scroll through the tabs by turning the mouse-wheel on the tab-bar.

    These features were provided by many addons such as:
    – FireGestures (mouse-wheel on tab-bar)
    – FLST (Focus Last selected tab) provided Tab-Flipping feature
    – Tab-Deque provided the same and similar other features


    It’s such a great loss seeing them gone. The developer of FLST also stated that he would like to re-implement it but he just can’t as you taken away the appropriate API, so users shouldn’t blame him but you 😉 as he stated here:

    I think not only the users (like me), bat also the developers like him and other developers are really NOT happy with that situation and would like to provide those features again. 🙁

    Would be great to see any proceedings in this aspect, in future versions…

    Best regards,