Firefox Sync uses a free Firefox Account to keep bookmarks, passwords, history, open tabs, and add-ons available across devices. Once each device signs into the same account, changes usually appear automatically within a few minutes.
Does this affect you?
Use this for Firefox on Windows, Mac, iPhone, or Android when you want browsing data to follow you between a computer, phone, tablet, or second laptop.
Turn on Sync for the first time
Create the account once, then sign in on your other devices.
- Open Firefox.
- Click the menu button or profile icon and choose Sign in, Sync, or Sync and save data.
- Create a Firefox Account if you do not already have one.
- Confirm your email address from Mozilla.
- Open Settings > Sync.
- Choose which data types to sync, such as Bookmarks, Passwords, History, Open Tabs, and Add-ons.
- On another device, install Firefox and sign in with the same email and password.
Fix Sync when data is not moving
Use these checks when both devices are signed in but bookmarks or passwords do not appear.
- Open Settings > Sync on each device and confirm the same Firefox Account email is shown.
- Click Sync now to force an immediate attempt.
- Check the internet connection on both devices.
- If one device still fails, sign out of Sync on that device.
- Restart Firefox and sign back in.
More control
Manage connected devices
Open Settings > Sync and review Connected devices, or sign in at accounts.firefox.com. Remove devices you no longer own or trust.
Signing out does not erase cloud data
Signing out of Sync removes or stops the local synced connection on that device. Data remains in your Firefox Account and on other signed-in devices.
A newsletter email is not always a Firefox Account
If Mozilla already has your email for another purpose, you may still need to create a Firefox Account specifically for Sync.
Sources
- Mozilla Support – How do I set up Sync on Firefox? (2025)
- Mozilla Support – Sync Firefox bookmarks, passwords, and more (2025)
- Mozilla Support – Firefox Sync not working (2025)