Do you use Firefox Sync? Why or why not?

Yes. Because I have too many devices. Firefox sync is easy except that I have to reconfigure settings for each add-on.
- I'm pretty sure I've seen some FF addons have an option to sync their setting via FF Sync.
- Does Chrome sync addon data? I am getting a bit annoyed by the fact that Firefox does not, but actually I don't remember if Chrome ever did this.
  
  It's not a question of the browser, it's the addon. There are separete APIs for local and synced storage (but same interface). Both browsers use the same main api (web extension).
- Ditto

Yep. It's e2e encrypted, and you can even self-host the sync server, if you don't want to rely on an external service. Pretty much a no-brainer.
- Have you hosted it yourself? I'm curious about doing it, if its not a hassle.
  
  Yea, it's pretty easy if you already have a server. All you need to do is run a docker container, and change the identity.sync.tokenserver.uri setting in about:config. On mobile you have to enable the debug mode by going to "Settings > About Firefox" and tapping the Firefox logo a few times, then go to the new "Sync Debug" settings entry.
  The container above only runs the sync-server though, you still have to log into a Mozilla account to use it. There is a replacement that includes the whole stack, but I haven't tried that one yet.

Yeah, I mainly use it for the "send tab to device X", love that feature so much!
- I wish this feature would work for me. I can send a tab from firefox on windows or Linux and it won't show up on Firefox for iOS at all, or sometimes it will show up after a long (5+ min) delay.
  
  Hmm that's weird, always worked flawlessly for me, I do also have my devices on the same VPN at all times though, maybe it's that? I also only use Linux and Android.
- I recommend KDE Connect, it also has this function. :)
  But sometimes I use this and sometimes I use that feature.
  
  I use that too thihi
- TIL 🤯
- I used to use that until I noticed that all open tabs for all logged in sessions are easily accessible through the menu or the "Firefox View"

I sync bookmarks between devices and sometimes send a tab from one device to another.
EDIT: I trust Mozilla way more than Google.
- You don't even have to trust them. Firefox Sync end to end-encrypts everything and the browser is open source, so you can even verify the encryption mechanism. No trust required.

Yes. I want to have access to both history and bookmarks on all my devices and send specific tabs to other devices. Sync makes these super convenient.

mostly just to send websites I find while on mobile to my PC so I can properly read/interact with them on my PC
- I do the same, just with xdg-open via ssh
  
  How do you use this with mobile devices?

Yes. For many years and couldn't do without it.

I use it for preferences and bookmarks and stuff. But I never save passwords in any browser, I have my password manager for that.

No, I don't need yet another account, nor do I have a need to sync anything.
I don't really use bookmarks, and haven't found much value in sharing anything between my devices. I just install ublock on new devices and that's about it.
- For me its mainly history.
  Having to type out full URLs for sites I've already visited on other devices bums me out.
  So does not being able to go back and look for that one thing in my history. When was that... was that on my phone, or my laptop, or my desktop...?

No. I tried it once and lost half my tabs and bookmarks. I assume because they were different on each device I synced. One overwrote the other. Maybe if I had brought an in-use device into a new browser installation it would have worked as intended. But I don't trust it won't lose things now. All my devices have their own set of things to sync.

yeah of course

Yes, because it's the only way I can save my phone bookmarks and share it directly with my computer. As a device that I carry with me almost all of the time, there are a lot of sites, articles and etc. that sometimes can't finish to read or explore when on the street or in a meeting with friends or whatever, so I just bookmark them to revisit it later at home from my laptop. Would prefer to export them to a file to avoid the use of a Mozilla account, but it's not possible on Android. At least not that I know of.

Yes, I trust the encryption layer and the Mozilla Foundation has good ethical principles. I'm also a big fan of Firefox Relay (email alias provider) to protect my inbox from spam.

I sync bookmarks, extensions and browsing history. I do not sync autofill or passwords. Credit cards are never saved to anything. I use KeePass for Passwords.

Religiously for more than 5 years now. I have the same things synced accross 4 computers and a phone.

I use it cause its convenient.

No, because I'm a fucking luddite or something.
Thing is, it's pointless to me. I don't need nor want all my devices to have the same configurations, bookmarks and history.
- you reinstall your os/get a new pc.
  you type in your password and 2fa code.
  your stuff magically syncs and all your favorite extensions are already inatalled and synced (including custom filters in uBO)
  
  you type in your password and 2fa code.
  I don't. I prefer writing down my passwords on a little notebook. It's ironic as hell that a "coded" paper note at my own home is more secure than anything on my computer
  all your favorite extensions are already inatalled and synced (including custom filters in uBO)
  I'm vanilla as hell, I just use default uBO and sometimes NoScript. To me, sync offers nothing of value.
- Tbf you can selfhost the sync
  
  Why would I want to do that?

using it, syncing my bookmarks with it between systems (work, home, laptop, phone, tablet)

No, I use my devices for different purposes and I don't have any interest in them communicating

Yes, but only on new installs to get all my extensions and settings. Then I disable it

Yes, because it helps me organize my horde of bookmarks that I need to sort and keep on task with my projects.

Yes. I sync everything but passwords and bookmarks.
- I get passwords. Why not bookmarks?
  
  I use the same account at work and at home, so I need to separate bookmarks.

I use it for open tabs only. I then monthly bookmark all of them on a desktop. Then I close all the tabs on my phone and start again.

Only on one instance, because I don't want the same bookmarks and set of extensions on every computer. I wish it were more configurable.

Yes, but it doesn’t synchronize all like the values in the about:config.
- Syncing all about:config values wouldn't work, since it contains lots of variables which are OS-specific or contain temporary values, like timestamps.
  If you want to synchronize specific values, you can create a user.js file in your Firefox profile folder and synchronize that via file sync or Git or similar.

No. Not for any good reason though... I just don't need it.
Firstly, I use LibreWolf rather than Firefox. It still has Sync but it's disabled by default and I've just never felt any interest in enabling it.
I use KeepassXC for passwords, so I don't need Firefox to sync those.
I don't use bookmarks. I don't have an amazing memory or whatever I've just always found it more convenient to just search for whatever I'm trying to find, whether that's searching my history or google or whatever. Like how do you organise bookmarks? Trying to categorise pages that I may wish to refer to in the future would drive me nuts. I do use Zotero which is similar to bookmarks but only for academic research.
Even transferring things between devices. That might be nice but seriously I just search for whatever it was I was looking at on whatever other device.
All that remains is addons and themes and honestly it's kinda nice to start with a clean slate on every new desktop and add in themes and addons. Only takes a minute.

No, because the set up page for it has never actually loaded for me. Ever

It's a great way to set up Firefox on a new device. Why wouldn't I want to install the same extensions and copy my bookmarks? I wish it also synced toolbar layout so I wouldn't have to remove those weird spacers Firefox adds around the address bar by default every time

Rarely, mostly due to accessing a cool website I found a few days ago on the device I am currently using

Nah, I dont use it. In fact, I go through and disable almost all the "extra" stuff in any browser I install. I'm of the "Do one thing well" school of thought, so all these apps trying to do everything, all at once, just to keep you in "their" system? No thanks. Sync offers absolutely zero features that don't have better, alternative options already.

I used it accidentally. Now my work PC and my personal laptop have a mishmash of unwanted bookmarks on each

I tried it at two separate times, and both times it would delete my tabs when I add a new device to sync. Maybe I used it wrong, but it just aggravated me to disable it quickly.

I use it, but when I experimented with data synchronization using Firefox Sync, it simply doesn't work, it is so unreliable and unpredictable that you can't bet on it. It's a real pity, because I wanted to use it for a cool thing, synchronizing data of one website, without having my own server for that website. It failed because Firefox Sync fails.

I love Sync!
Except on iOS, where my bookmarks and passwords never actually synch, because it's not really Firefox but a weird skin on Safari because... Apple.

I wouldn't have it any other way. I need to have my desktop and phone browsers synced.

Nice try FBI...

- Firefox Sync is end-to-end-encrypted, meaning your data gets encrypted before upload and decrypted after download. The encryption key, i.e. your password, never leaves your computer. The way a password reset works, is by simply erasing your data from the server and then re-uploading from your Firefoxes. This means, if law enforcement or attackers get data from Mozilla's servers, they can't do anything with your Sync data.
  I'm on board with being sceptical about security, but this is one of the simplest and most bulletproof approaches.
- ff sync data is encrypted locally, on your machine.