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Waterfox × Tree Style Tab: A Collaboration for the Waterfox Sidebar

I’m happy to announce a collaboration with Tree Style Tab (TST), the popular Firefox add-on that brings a unique and powerful tab management experience to Waterfox. This partnership, made possible by the sponsorship of the Waterfox project, is bringing a native sidebar solution for Waterfox users, offering improved, advanced functionality without the need for third-party extensions.

What’s coming to Waterfox?

Inspired by the web browsers of yore, and something I’ve been wanting for quite a while are tab previews in the vertical sidebar. This will be the default view when enabling the sidebar.

Sidebar tab preview

You are also able to toggle the sidebar to be on the left or the right side of the browser window.

Keeping to its namesake, you are also able to have a tree style tab previews.

Tree style tab previews

And of course, when the tabs become too numerous you can collapse them to the familiar text-only mode.

Familiar tree style tabs

You will also have a myriad of customisations options as one would expect from Waterfox, styling your browser however you see fit.

Customised Waterfox

Boosting Performance with Virtual Scrolling

One of the key improvements made possible by this collaboration is the integration of virtual scrolling technology. This innovative approach addresses a long-standing performance bottleneck in TST. Previously, all tabs, even those hidden, were rendered in the background, consuming significant resources.

What’s Changed?

With virtual scrolling:

  • Nodes are only loaded for visible tabs, dramatically reducing memory usage and improving rendering speed.
  • Cached sidebar content is no longer needed, further streamlining performance.
  • This optimization uncovers other potential performance issues, allowing for further refinement.

Benefits for Everyone

This performance boost benefits both Waterfox users and TST itself:

  • Waterfox users experience faster tab switching, smoother scrolling, and reduced memory consumption.
  • TST development can now address other performance areas thanks to the virtual scrolling foundation.
  • In-tab previews in Waterfox become even more efficient with reduced resource usage.

Beyond Waterfox: Open Source Collaboration in Action

It’s important to remember that while this native integration brings incredible benefits to Waterfox users, it’s powered by the collaborative spirit of open source. Tree Style Tab itself is an open-source project, meaning its development thrives on community contributions and shared knowledge.

Waterfox’s Impact

”[The virtual scrolling architecture] is the largest benefit on the TST project… Current TST keeps DOM nodes as tabs in/around visible area in the sidebar, it improves total performance around rendering and initialization,” explains Yuki Hiroshi, the TST developer. He further adds, “Introducing virtual scrolling minimizes the RAM usage from such additional contents."

"Now I could develop TST at work time of my employer company, as a task sponsored by the Waterfox project, so I could take enough time to research how we can introduce virtual scrolling to the existing implementation without breakage.”

The Waterfox sponsorship allowed the TST developer to focus on crucial features like virtual scrolling and UI enhancements, which significantly improve performance and responsiveness, particularly noticeable for Waterfox users experiencing these features natively.

While Waterfox played a role in enabling these advancements, it’s important to note that the improvements benefit all TST users, regardless of their chosen browser. The virtual scrolling architecture reduces memory usage and enhances rendering speed, making tab management smoother and faster across the board.

Open source thrives on collaboration, and advancements made for one project often benefit the entire community.

Waterfox in 2023: Evolution, Independence, and Forward Momentum


In 2023, Waterfox underwent significant changes. This pivotal year brought a refreshed website, regained independence, and several important releases.


Waterfox has regained its independence, re-emphasising something that I hold import to this project — putting users first. This shift allows the company to iterate a bit faster and focus more on user privacy and customisation.

Website Revamp

The Waterfox website got a complete makeover, offering a more intuitive experience. With a fresh design and improved functionality, the goal is to make the website a bit more informative for new users.

Notable Releases

Android App Launch

Waterfox expanded its reach with the launch of the Android app. This addition lets users enjoy the same privacy-focused browsing on their mobile devices.

DNS over Oblivious HTTP

In collaboration with Fastly, Waterfox introduced DNS over Oblivious HTTP, ensuring user privacy and a secure browsing experience.

Ongoing Developments

Vertical Tabs on the Horizon

Vertical Tabs are in full-time technical planning. Expected for testing between Q1 and Q2, Waterfox is excited to announce a new partnership, promising a solid improvement on most other experiences out there.

Android Upgrade, WebExtensions Support, and Darker Dark Theme

Waterfox is actively upgrading its Android app and ensuring support for all WebExtensions. This includes moving to a monthly rolling release, keeping up with the latest Android Components versions, instead of sticking with ESR. Additionally, a sleeker, darker theme is in the works for those who prefer a darker tones in the UI.

A privacy-focused search project, teased earlier, is nearly ready for a closed beta. Stay tuned for announcements!

Future Endeavours

Looking ahead, Waterfox is set for growth and improving the browsing experience. Plans include improving user privacy, introducing a few new features, and expanding community initiatives.

The year 2023 was a milestone-packed journey for Waterfox! As we move forward, I extend my heartfelt thanks to the community for your support. Here’s to a great 2024!

Waterfox in Partnership with Fastly

We’ve teamed up with the stellar folks at Fastly to help power a new privacy technology, DNS over Oblivious HTTP (DoOH).

Whenever you browse the web, your DNS queries get exposed to your ISP or anyone else watching your web traffic. That means they can easily see which sites you visit and profile your interests. Rather invasive, isn’t it? ​

Waterfox has partnered with Fastly to integrate secure Oblivious HTTP relays into the browser’s DNS resolution — with this partnership, we are able to use a world-class implementation of this privacy-respecting protocol, that’s also used by many of the world’s leading platforms, including many top internet browsers. This encrypts and relays your DNS traffic through remote servers in a way that completely hides the target of your DNS queries -– and ultimately the site where your browser is planning to connect. Your DNS requests become significantly more private and secure.

​ It is important that at every stage of the connection each service is run by an independent third party. This prevents any one party from collating data together and unmasking who is making the requests.

​ Fastly operates a huge global network of edge compute locations that make this privacy relay work fast and reliably, which means there will hardly be a performance penalty when using DoOH.

​ The DNS resolver will be Cloudflare’s service, which is also an independent third party.

​ For us, this is a huge step in our mission to make Waterfox one of the most privacy-respecting browsers out there. Your data belongs to you, and we’ll keep working nonstop to protect it. Teaming up with Fastly brought some serious privacy superpowers to the table. We can’t wait for you to try it out!

​ Over the weekend, DNS over Oblivious DNS infrastructure was migrated over to Fastly. And as always, keep spreading the word to anyone who cares about internet privacy in this age of surveillance. We’ve got your back! ​


Q: Do you have access to the relay?

A: No, Fastly will independently manage the relay, and we don’t have direct control over the code, the service configuration or the TLS certificates. This is critical from a privacy hygiene standpoint.

Q: Will Fastly have access to my data?

A: No, due to the double-blinded nature of the OHTTP service. One layer, Fastly, handles end user identifying metadata (the Relay) while another handles the end user’s request data (the Gateway). These two layers communicate but do not collude, and do not pass identifying details about the Client to each other.

Q: Is this slower than making normal DNS requests?

A: Slightly, but not by much. Cloudflare ran tests and found that the penalty is consistently less than 1ms at the 99th percentile1,.

Q: I still don’t understand - why must the relay and resolver be run by independent parties?

A: As explained by Fastly2, the privacy guarantees relies on one fundamental property — that the proxy and the target servers do not collude. So long as there is no collusion, an attacker succeeds only if both the proxy and target are compromised. ​




A New Chapter for Waterfox

Dear Waterfox Community,

Today marks a new change for Waterfox.

Over the years, Waterfox has grown and flourished, thanks to the unwavering support and enthusiasm of its incredible community. Your passion for a privacy-focused and customisable browsing experience has been the driving force behind the success of this project.

I am happy to say that Waterfox is independent again. This change allows the community and myself to shape the browser’s future direction.

As we embark on this new chapter, Waterfox’s dedication to privacy, customisation, and performance remains. I am committed to delivering a browser that prioritises your online security and respects your digital autonomy. With this change, I have the opportunity to accelerate development, introduce new features, and focus on the user experience.

One of the most valuable aspects of Waterfox is its vibrant and passionate community of users. I am grateful for your support, feedback, and contributions over the years. Your input will continue to guide the evolution of Waterfox as we meet your expectations.

In the coming months, I will be working diligently to advance the browser, focusing on improvements that enhance privacy, boost performance, and expand customisation options.

Stay tuned for future updates, as I will be sharing more details about my plans for Waterfox, including new features and opportunities to get involved.

Thank you for your continued support!

Alex Kontos Founder, Waterfox

Reblog: How the Open-Source Browser Continues to Balance Performance, UX, and Customizability with a Focus on Privacy

TL;DR: Waterfox delivers a balanced browsing experience for users to navigate the web with peace of mind. Leveraging privacy and usability, Waterfox enables users to add customizations and optimize their time on browser-based applications while protecting their online activity. Waterfox schedules timely releases to improve user experience and has more accessibility in-store, with an Android platform in the works.

Read the full article at HostingAdvice.