Firefox Profiles let you run completely separate browser instances with different settings, extensions, and history. Here's when they're useful and how to set them up.
What a Profile Contains
Each Firefox profile is an independent environment with its own:
- Extensions (including settings)
- Bookmarks and history
- Passwords and logins
- Cookies and sessions
- Preferences and about:config settings
- Themes and UI customization
Profiles do NOT share any of this. It's closer to having two separate users on the same OS than to having two windows open.
Profile vs. Containers vs. Private Mode
| Feature | Profiles | Containers | Private Mode |
|---|---|---|---|
| Separate cookies | Yes | Yes (per-container) | Discarded on close |
| Separate extensions | Yes | No | No |
| Separate settings | Yes | No | No |
| Separate history | Yes | Yes | Discarded on close |
| Can run simultaneously | Yes (separate windows) | Yes (same window) | Yes |
Use containers when: You want multiple accounts on the same site in the same window.
Use profiles when: You want completely different browser environments (different extensions, different settings, different everything).
Setting Up Profiles
Profile Manager
firefox -ProfileManager
Or: about:profiles in the address bar (simpler, works without closing Firefox).
In the Profile Manager or about:profiles:
- Click "Create a New Profile"
- Name it (e.g., "Work", "Dev", "Personal")
- Choose where to store it (default location is fine)
Launching a Specific Profile
# Launch with a specific profile by name
firefox -P "Work"
# Launch a new window with a specific profile (while another is running)
firefox -P "Work" --no-remote
The --no-remote flag forces a new Firefox instance rather than opening a window in the existing one. Without it, Firefox will try to reuse a running instance.
Desktop Shortcuts
Create separate desktop shortcuts for each profile:
# Linux .desktop file example
[Desktop Entry]
Name=Firefox (Work)
Exec=firefox -P "Work" --no-remote
Icon=firefox
Type=Application
On macOS, you can use a shell script or Automator app:
#!/bin/bash
/Applications/Firefox.app/Contents/MacOS/firefox -P "Work" --no-remote
Common Profile Setups
Work / Personal Split
- Work profile: Work Google accounts, corporate bookmarks, Slack web, work-related extensions (password manager synced to work vault)
- Personal profile: Personal accounts, media extensions, personal bookmarks
Developer Profile
- DevTools settings tuned (dark theme, debugger paused on exceptions)
- Extensions: uBlock Origin (to test with/without), React DevTools, Axe accessibility checker
- No saved passwords (test with clean credentials)
- Possibly
about:configtweaks for development (CORS exceptions, local HTTPS)
Clean Testing Profile
- No extensions
- Fresh cookie state
- Used for testing how sites look to new visitors
Privacy / Research Profile
- Strict tracking protection
- uBlock Origin in hard mode
- No persistent cookies (
privacy.sanitize.sanitizeOnShutdown = true) - Used for researching sensitive topics
Syncing Profiles
Firefox Sync is tied to one Firefox Account. If you want Sync across multiple profiles:
- Each profile needs to sign into the same account (for same-device sharing)
- Or different profiles can use different Firefox Accounts (for truly separate environments)
Syncing the same account to multiple profiles on the same device will sync data between them. This may not be what you want if the point is to keep them separate.
Backing Up a Profile
When you create profiles, they're stored in:
-
Linux:
~/.mozilla/firefox/ -
macOS:
~/Library/Application Support/Firefox/Profiles/ -
Windows:
%APPDATA%\Mozilla\Firefox\Profiles\
Back up the profile folder periodically. To restore, copy it back to the same location and point the Profile Manager at it.
Tab Sessions Across Profiles
One limitation of profiles: if you have saved sessions in one profile (say, your work profile), you can't access them from another profile without exporting.
Tab Manager & Session Saver stores sessions as JSON — you can export a session from one profile and import it into another by copying the JSON data. This is useful when you start work-related browsing in your personal profile and want to move it over.
Firefox Developer Edition and Nightly
Two special Firefox variants worth knowing:
- Firefox Developer Edition — separate install with developer-focused defaults (extra DevTools features, no auto-updates that break your setup mid-debugging)
- Firefox Nightly — bleeding edge, gets features months before release, useful for testing compatibility
Both can run simultaneously with regular Firefox since they create separate profiles by default. Useful setup: Nightly for daily driving to catch issues early, Stable for production debugging, Developer Edition for focused development work.
Top comments (0)