Firefox 87 Introduces 'SmartBlock' Private Browsing Feature to Fix Websites Broken By Tracking Protections

Mozilla has released Firefox 87 for Macs, Windows, and Linux machines, introducing a new intelligent tracker blocking mechanism called SmartBlock.

mozilla firefox banner
Since 2015, Firefox has included a built-in Content Blocking feature that automatically blocks third-party scripts, images, and other content from being loaded from cross-site tracking companies in Private Browsing windows and Strict Tracking Protection Mode.

Mozilla recognizes that the feature sometimes blocks legitimate elements of websites which can cause them to malfunction. SmartBlock aims to provide a solution to this problem without compromising user privacy. From the company's blog:

In building these extra-strong privacy protections in Private Browsing windows and Strict Mode, we have been confronted with a fundamental problem: introducing a policy that outright blocks trackers on the web inevitably risks blocking components that are essential for some websites to function properly. This can result in images not appearing, features not working, poor performance, or even the entire page not loading at all.

To reduce this breakage, Firefox 87 is now introducing a new privacy feature we are calling SmartBlock. SmartBlock intelligently fixes up web pages that are broken by our tracking protections, without compromising user privacy.

Mozilla says SmartBlock works by providing local stand-ins for blocked third-party tracking scripts that behave "just enough" like the original ones to make sure that the website works properly.

The stand-ins come built-in to Firefox, so no third-party content from the trackers is loaded by the browser, meaning they can't track users this way. According to the developers, SmartBlock will silently stand in for several common scripts classified as trackers on the Disconnect Tracking Protection List, and should provide a noticeable performance improvement while browsing.

The previous version of the browser introduced Total Cookie Protection, which is designed to stop cookies from tracking users across the web. Firefox 87, the latest update, is available now from the Mozilla website.

Popular Stories

iphone 17 models

No iPhone 18 Launch This Year, Reports Suggest

Thursday January 1, 2026 8:43 am PST by
Apple is not expected to release a standard iPhone 18 model this year, according to a growing number of reports that suggest the company is planning a significant change to its long-standing annual iPhone launch cycle. Despite the immense success of the iPhone 17 in 2025, the iPhone 18 is not expected to arrive until the spring of 2027, leaving the iPhone 17 in the lineup as the latest...
apple intelligence black

Report: Apple's AI Strategy Could Finally Pay Off in 2026

Tuesday December 30, 2025 9:01 am PST by
Apple's restrained artificial intelligence strategy may pay off in 2026 amid the arrival of a revamped Siri and concerns around the AI market "bubble" bursting, The Information argues. The speculative report notes that Apple has taken a restrained approach with AI innovations compared with peers such as OpenAI, Google, and Meta, which are investing hundreds of billions of dollars in data...
apple fitness 2026 1

Apple Teases 'Something Big' Coming Soon to Apple Fitness+

Tuesday December 30, 2025 2:11 pm PST by
The Apple Fitness+ Instagram account today teased that the service has "big plans" for 2026. In a video, several Apple Fitness+ trainers are shown holding up newspapers with headlines related to Apple Fitness+. What's Apple Fitness+ Planning for the New Year? Something Big is Coming to Apple Fitness+ The Countdown Begins. Apple Fitness+ 2026 is Almost Here 2026 Plans Still Under ...
iphone 17 pro dark blue 1

iPhone 17 Pro and Pro Max Users Report Static Speaker Noise While Charging

Tuesday December 30, 2025 10:39 am PST by
iPhone 17 Pro and Pro Max owners are having trouble with the speakers of their devices, and have complained about a static or hissing noise that occurs when the iPhone is charging. There are multiple discussions about the issue on Reddit, the MacRumors forums, and Apple's Support Community, where affected users say there is a noticeable static noise "like an old radio." Some people report...
maxresdefault

Hands-On With a Rough iPhone Fold Mockup

Monday December 29, 2025 10:55 am PST by
Apple is rumored to be introducing a foldable iPhone in September 2026, and since it will bring the biggest form factor change since the iPhone was introduced in 2007, curiosity about the design is high. A 3D designer created an iPhone Fold design based on rumors, and we printed it out to see how it compares to Apple's current iPhones. Subscribe to the MacRumors YouTube channel for more ...
maxresdefault

Where's the New Apple TV?

Monday December 22, 2025 11:30 am PST by
Apple hasn't updated the Apple TV 4K since 2022, and 2025 was supposed to be the year that we got a refresh. There were rumors suggesting Apple would release the new Apple TV before the end of 2025, but it looks like that's not going to happen now. Subscribe to the MacRumors YouTube channel for more videos. Bloomberg's Mark Gurman said several times across 2024 and 2025 that Apple would...
Mac Pro Feature Blue

What's Happening With the Mac Pro?

Wednesday December 31, 2025 9:59 am PST by
Apple hasn't updated the Mac Pro since 2023, and according to recent rumors, there's no update coming in the near future. In fact, Apple might be finished with the Mac Pro. Bloomberg recently said that the Mac Pro is "on the back burner" and has been "largely written off" by Apple. Apple apparently views the more compact Mac Studio as the ideal high-end pro-level desktop, and it has almost...
macbook air march 2020

Apple Says Final Intel MacBook Air and Apple Watch Series 5 Now 'Vintage'

Wednesday December 31, 2025 8:39 am PST by
Apple today added the final 13-inch MacBook Air powered by Intel processors, the Apple Watch Series 5, and additional products to its vintage products list. The iPhone 11 Pro was also added to the list after the iPhone 11 Pro Max was added back in September. The full list of products added to Apple's vintage and obsolete list today: MacBook Air (Retina, 13-inch, 2020) iPhone 8 Plus 128GB ...

Top Rated Comments

Nozuka Avatar
62 months ago
I love their Container feature. You can create seperate "Cookie containers" for websites like Facebook, Youtube, etc.
That way you will keep your settings on these websites, but when you visit other websites, they can't abuse these cookies for tracking you, since they are not available there. Or a seperate container for e-banking.

It also allows you to have several containers for the same website, so you can use more than one user on the same website. Very convenient if you have a personal and a business Office 365 account, for example.

Requires the extension from firefox: "Multi-account Containers" to make full use of it.
Score: 32 Votes (Like | Disagree)
wanha Avatar
62 months ago
Never been much of a Firefox user, but I applaud Firefox for their actions on privacy.
Score: 25 Votes (Like | Disagree)
adrianlondon Avatar
62 months ago

Never been much of a Firefox user, but I applaud Firefox for their actions on privacy.
I'm surprised that Firefox actually runs faster on my MBA (Big Sur latest beta) than Safari, although I think that's due to the amount of stuff it natively blocks, along with uBlock Origin, rather than any rendering advantages.

Two main reasons I prefer Firefox. (1) cookie control especially with Containers and (2) the way going to previous pages while reading forums doesn't reload and send pages pack to the top. Oh, and (3) uBlock Origin.
Score: 21 Votes (Like | Disagree)
Bandaman Avatar
62 months ago
Dunno what's going on with Firefox lately, but it's ridiculously fast on my Mac.
Score: 13 Votes (Like | Disagree)
MJaP Avatar
62 months ago
I always use Firefox on my Windows PCs, I've found it fast and secure. Best alternative to Safari in my opinion.
Score: 9 Votes (Like | Disagree)
Bandaman Avatar
62 months ago

Faster than Safari?
Yes. Much. And if you go into about:config and up the process count from 8 to say ... 100 ... it's comically faster. This is easily faster than Chrome, Edge, Safari, and Brave. It's also incredibly smooth and stable. Just the whole feel of this version of Firefox is really great. This will be my main browser again for a while and I've been on brave for quite some time. Also, the ad blocking by default on iOS is really great, even blocks stuff Brave seems to miss. I don't see most ads on websites with Firefox when I set it to strict mode.

Another very important point ... I can open a million tabs in Firefox and nothing slows down. Like ... at all ... and all the websites are responsive. I'm honestly impressed. Hopefully these great strides in the Firefox experience keeps them from disappearing. We need more non-Chromium browsers competing with Google. Sucks that Google basically owns 90% of the browser use market with either Chrome or a Chromium-based browser ... so much that even Microsoft caved in. I'm glad to support Mozilla for not being like everyone else.
Score: 6 Votes (Like | Disagree)