for the firefox, I can set a zoom level for a domain, and then FF will remember this zoom level for every page of this domain for all the tabs.

However, for Tor, it can only keep a zoom level for a tab, for this tab, any page, no matter from same domain or not, is display in the changed zoom level. But if I open a subpage from a domain I have set a unique zoom level, the new tab always display in the default 100% level.

It seems that in Firefox, the zoom level is bound to domain name; while in Tor, it is bound to tab. How can I change tor to the "firefox mode" to remember zoom levels according to domain?

To set them for each time I start Tor (once a day) is acceptable, but I dont want to set the same zoom level for same domain for every tabs of that domain. That drives me crazy.

And will this weaken my anonymous level?

Thanks in advance.

  • yes, this will weaken your anonymous level... so this behavior is on purpose. Oct 18, 2019 at 21:26

1 Answer 1


Tor Browser doesn't remember the zoom levels in order to reduce your browser fingerprint. In fact, having variable zoom levels per page could actually make you more unique.

That being said, you can change your settings in order to remember zoom. This involves changing the browser.zoom.siteSpecific property. By default, the browser will resist this change and restore defaults once you close the browser. Here's how to make your modifications stick:

  1. In the URL bar, enter about:config. This will show you a warning page. For good reason! Proceed with caution by clicking "I accept the risk".
  2. In the search bar, start searching "resist". You will see the option, privacy.resistFingerprinting. Double-click it to toggle it to false. It will look as such: resist fingerprint false The modified property is emboldened.
  3. Next, search for "zoom". Double-click to toggle the browser.zoom.siteSpecific to true. Here's what it should look like: zoom true
  4. Then restart your browser. It should now remember zoom levels.

You can always revert these changes later if you're worried about fingerprinting. Once you revert the privacy.resistFingerprinting modification, then browser.zoom.siteSpecific will automatically change to the default.

Hope this helps. It worked for me, and I'm sure it will for you too :D

  • Thank you, and I have succeeded in this way. But since every time the zoom levels are reset to default value, and since I (and i guess for many ppl) wont set the zoom levels totally same for each time, I really doubt the necessity to bind zoom level with other settings in the "resist fingerprint" cover enforcefully.
    – Jules Liu
    Oct 26, 2019 at 13:35
  • And I guess this can be solved by inducing a random micro changes of the zoom levels for each site. For example, If I set .stackexchange.com for 120%, then for every 5min or 10min, or every new tab of stackexchange, the zoom level will be set to a random value between 116-124%. I guess this will satisfy users' experience while remaining anonymous well, and ppl wont need to take other risks by unchecking "resistfingerprint".
    – Jules Liu
    Oct 26, 2019 at 13:43

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