Is there some privacy concern on using Firefox Sync to sync history across devices? I mean can I trust it?

2026-04-17 18:52 UTC

I wonder if they’re using my data to something or spying on me. Because I use Firefox Sync to sync mostly my history. I don’t have bookmarks, I just remember what site I want to access by its URL then I start typing and the autocomplete do the rest. For example, to access Lemmy I just type “le” because the only site I most access and starts with “le” is “lemmy.world”. Rarely I get some conflict on this approach. And it works on both my phone and desktop. I wonder if should I change this approach to avoid Firefox Sync or I can trust on Firefox Sync.

Replies (7)

@peskypry@lemmy.ml 2026-04-18 10:15

It is e2e encrypted and just works. Everything in Firefox Sync is encrypted including Bookmarks, History, Passwords etc.

Open ##1328465
@IratePirate@feddit.org 2026-04-18 05:47

I've moved to Floccus (which can sync browser tabs and bookmarks via Nextcloud Bookmarks). Does the essential parts for me.

Open ##1328466
@GlenRambo@jlai.lu 2026-04-17 21:56

Just checked LibreWolf a hardened Firefox as I thought they disable it. Turns out its just off default and "There aren't significant downsides as Firefox Sync encrypts your data locally before transmitting it to the server." I thought there might be another reason to have it off (giving Mozilla your email?) but seems OK. https://librewolf.net/docs/faq/#can-i-use-firefox-sync-with-librewolf-is-it-safe-to-do-so

Open ##1328467
@kylekatarn@lemmy.world 2026-04-17 19:00

> Securing your data with Sync involves creating a unique password, which plays a crucial role in encrypting your data for complete privacy. This encryption is end-to-end: your data is encrypted before it ever leaves your browser and can only be decrypted by another instance of Firefox. Once your data reaches a Mozilla-operated server for storage, it's already in an encrypted state, ensuring that not even Mozilla can access or decrypt this information. [support.mozilla.org/en-US/kb/sync](https://support.mozilla.org/en-US/kb/sync#w_is-it-secure)

Open ##1328468
@Ismael@bohio.icu 2026-04-17 19:00

From their [website](https://www.firefox.com/en-US/features/sync/) > All your data is encrypted on our servers so we can't read it – only you can access it. We don't sell your info to advertisers because that would go against our data privacy promise.

Open ##1328469
@PierceTheBubble@lemmy.ml 2026-04-18 01:07

I would say the feature is quite easily avoidable, as it only seems to require one manual visit, for it to show in the suggestions; which I believe are sorted based on interactions with pages (so just interact more with pages, you want to be suggested more strongly). I would personally advise against using the feature, primarily because it ties all browsers, on multiple separate devices, to a common Mozilla account. So why broaden your attack surface, for advantages easily reproduced manually? Is the little bit of added convenience, worth the (potential) trade-off?

Open ##1328470
@bridgeenjoyer@sh.itjust.works 2026-04-18 21:22

I love that feature tbh. Glad I can trust it. I use waterfox tho

Open ##1695426