Sleipnir 4: A Deconstructed Web Browser

About a year ago we published a review on a up-and-coming web browser called Sleipnir, giving it a great score and calling it a browser you just have to try. Recently a new version of the browser for the Mac has come out, and when we saw that the developer was calling it “the most advanced web browser yet”, we knew we had to take a look at it once more.

In our previous review, we praised Sleipnir for its sleek, clean cut design and its innovative tab navigation. How does the new one fare in these categories, and what’s new in it? Let’s check it out.

Sleipnir 4



Sleipnir is a Webkit-based browser with a super sleek and minimal design, as well as some pretty awesome features that you likely haven’t seen on any other browser. Version 3 is the one that we reviewed a while back, but today we’ll be taking a look at Sleipnir 4, which just came out a few days ago.

The most noticeable change in the new Sleipnir is the design. While the old version stood out for its simplicity, this new one has even less elements and everything is more organized and tightened up. What exactly am I talking about? Let’s take it by parts.

Thumbnail Tab Navigation

Thumbnail Tab Navigation

Thumbnail Tab Navigation

The improved thumbnail tab navigation, which is a trademark of the browser, is easier on the eye and ideal for working with a large number of tabs. Instead of shrinking your tabs as you open more of them, Sleipnir makes a cover-flow-like scrollable list of your thumbnails while displaying the original size of each of them, making it easier to identify your tabs even when you’re dealing with a lot of them. The title of each tab is hidden, but it will be shown under the thumbnail as you hover over your open tabs. This is one way Sleipnir keeps its design clean while not regressing on its functionality.

Portal Field

Portal Field

Portal Field

Portal Field is the name that the navigation bar receives in Sleipnir. It doubles as a search bar and it is kept discretely on the top right side of the browser, only slightly coming into attention by expanding to the center when activated.

The best part about it is its lightning-fast predictor which is also pretty smart and organizes your predicted results in a very neat way. For example, instead of showing you a billion results from your history of the same site, it will only show you one line with the title of the site, which you can then expand to view the pages that you’ve visited in it. Portal Field also has the ability of sending search queries directly to customizable sites, like Amazon or Wikipedia.

Address bar

Address bar

The current tab’s address is separated from the Portal Field, as it is located right above it in order to save space. Only a few characters of the address will be displayed, but if you click on it, you can get a full view of the address and copy it or modify it.




TiledTab is similar to Safari’s Tab View, but on steroids. Not only does it give you a view of every tab you have open, but it also gives you 6 “spaces” where you can keep a number of different tabs. This way, you can have a space for procrastinating and social networks, another for serious work, and so forth. I found this really useful, as staying on one space with only a few tabs open makes it harder to lose attention while working by switching over to a time-wasting site. These spaces marked a line between the sites I should be and shouldn’t be spending time on.



This also makes it easier to work with a big number of tabs. I tend to leave everything open for use later, so I started using one my spaces as a “temporary” folder of links that I’d like to get to later, just to get them out of my way when I’m doing something important.

Minor Details



Sleipnir also has a few minor things that I found really nice. For example, everytime you select text, a little menu (similar to PopClip) will pop up next to your cursor with a few buttons to search, define, or copy your selection.

The app also has its own syncing service called Fenrir Pass, with which you can sync your Sleipnir settings across multiple devices, and access certain web services. It also implements its own homepage which will include a few links that might be of interest to you based on what you normally browse.


Sleipnir Gestures

Sleipnir Gestures

One of my favorite things on my Mac is the many gestures that I have set up. I use a very handy app called jiTouch, that implements multi-touch gestures system-wide, and I have one for pretty much everything. Quitting apps, closing windows, switching between tabs, you name it.

Sleipnir, as well, has its own gestures for navigating, but they are much different than jiTouch’s. While jiTouch’s gestures are all based on finger taps and swipes (combining two or three fingers to create a large list of possible combinations), Sleipnir’s are all based on swipe gestures that you can do with two fingers, making you pretty much draw certain shapes to trigger actions.

Two-finger swipes to the right or left will switch your current tab (unlike the back-forward actions that they trigger on Safari and Chrome), and you also have some more complex gestures for closing tabs, re-opening them, and reloading them. They’re also more interactive, as they are accompanied by animations that announce when a gesture is triggered. These are easier to remember, but less convenient to use than Jitouch’s, and if you have them both activated, things can get pretty confusing.

A Few Bugs

When I first started using Sleipnir, it kept crashing on me while I was trying to import my contents from Chrome. I tried it a few times and everytime I did the import, it crashed. Same with Safari’s content, so I had to do a clean install of the app. When I finally got it to run, it turned out all of those imports actually did work (therefore I had around 5 of them), it was just the importing window that was crashing on me.

I also experienced a few crashes while using the app to browse around. These all appeared to happen while in the tab tile view, and weren’t too frequent, but they do speak a lot about the stability of this release. Just as well, working with pages that hold sessions (like WordPress) turned out weird and confusing, as Sleipnir kept reloading the pages as I was working, and not always saving my work. This was, as you might imagine, very frustrating.


Using Sleipnir feels exciting, like using a new cool gizmo or something. Sleipnir’s devs have deconstructed the concept of a web browser and kept only the visual bare minimum to keep a focused and pleasant browsing experience. It’s certainly a very pretty app, and it has some great features that I hadn’t seen anywhere else, like its unique thumbnail tab navigation.

Unfortunately, I can not say that I would keep using it. The absence of extensions is still a big problem, and that’s where much more established competitors like Safari and Chrome beat this app. Maybe I’ll keep using Sleipnir for certain specific tasks, but I can’t imagine it right now becoming my main browser. It feels very close, but it’s not yet quite there.

But what about you? Have you tried Sleipnir? If you haven’t, I’d suggest you at least give it a peak just to see what’s out there. Maybe it’ll grab your attention.


Sleipnir deconstructs the concept of a web browser to keep only the visual bare minimum to keep a focused and pleasant browsing experience.

  • Ngoc Pham

    I tried and quite like the browser but one thing that turns me away is Extensions. At the moment, you can’t use any extension (Safari or Chrome) with Sleipnir at all. It would be painful to surf without essential extensions like LastPass and AdBlock.

    • Lê Hùng Thiện

      I love this brower though it still has several bugs but at all, it’s quite good!
      It also has a feature called “Ad Block”, I haven’t try it but you can try if you want.

  • Charnita Fance

    It sounded great until you said that extensions are not supported. I MUST have extensions! I actually read this entire review word-for-word (something I don’t often do), and I was really sold on it. As you stated in your conclusion, I may try it and just use it for specific task as well. I’ll at least give it a try just to see if I like it.

  • Mark

    I would be sold If you could use 1password with this

  • urbanlegend

    The touch gestures should be improved, at least give the user a choice or customize them so they’ll be “Mac friendly”. For example every time I try to go back with the same two/three finger swipe like in Safari it doesn’t work.

    • danny


      Customisable gestures would be awesome.

  • iCrazy

    That’s why I love Sleipnir and wish that they have made an identical version for tablets (waiting for the update). In comparison Safari looks like an unoriginal grandpa.

  • Mihai Neacsu

    This little guy has huge potential (that’s what she said). I think the devs did a fantastic job and that all the features we’re missing we’ll be implemented in time.

  • otak

    Sleipnir is a great browser. I use it as my main browser for a long time. And I should say two things:
    If you want something to be fixed (or implemented), you can write to the developers, they will answer you in most cases and try to do something for you (or at least explain why something functions that way).
    If you see some crashing, just wait for a while and update your browser (especially if you reported the bug). Updates are released quite often.

  • daniel

    I find being able to at least see the address bar is of more importance than it seems – making sure you’re on the correct site (security), debugging, etc.; obfuscating or hiding it can make things very tricky. Also, I noticed that I visited local dev sites the browser was adding .com to the end and causing issues – e.g.: testsite/.com (only I didn’t know this because the address was not available). Visual tabs are nice but beyond that I don’t see any compelling reason to keep using it…

    • Dan

      Thanks for pointing that out Daniel!
      That “local development” issue makes the app unusable for me.

  • KevinPsalmon

    I tried it too, it seems fantastic but too much bugs at the moment :(
    Too, no plugin, no Ad Block (the integrated one doesn’t work), etc… i’m waiting for the next update !

  • danny

    This has been my main browser for months now. For me, the gestures are so commonplace, when I do use another browser, I forget that it isn’t Slepnir and try to use the gestures to do things. Yes, there are a few bugs, for a while before they updated to v4, the browser would just hang and give me the beach ball for a few seconds and then keep going, but they seem to have addressed that issue. The devs are really good with feedback, once in a while I will report a bug and 9/10 times, it will be fixed in the next release. Releases are fairly frequent as well. It is a bit frustrating without extensions also, but I have found workarounds for most of the ones I use (mostly bookmarklets) that seem to do the job for now (would still like a decent ad blocker however, the inbuilt one is useless, Glimmerblocker seems to work reasonably well though). Judging from what I’ve seen on Sleipnir’s release blog, extensions aren’t too far away though. Overall, I love this browser and I couldn’t imagine my workflow without it.

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