Privacy guide
Firefox containers vs profiles: what each one keeps apart
Containers and profiles both keep parts of your browsing apart in Firefox. They draw the line in different places. This guide checks each one against Mozilla’s own documentation, item by item.
Direct answer
Firefox containers vs profiles comes down to how much you need kept apart. Containers separate cookies, site storage and cache inside one profile. They share history, bookmarks, saved passwords and extensions. Profiles separate all of that stored data. Neither one gives you a new fingerprint, because both run the same Firefox on the same computer. Neither one changes your IP address unless you add a proxy, or a Mozilla VPN location per container.
What Firefox containers separate, and what they share
Firefox has built-in container tabs: turn on “Enable Container Tabs” in Settings, under Tabs. Mozilla’s Multi-Account Containers extension adds more. It can assign a site to a container and sync container names. It can also set a proxy or a Mozilla VPN location per container.
Firefox already keeps third-party cookies in a separate jar for each site, through Total Cookie Protection. Containers add what that does not: two logins to the same site, side by side. Mozilla’s wiki page for the Contextual Identity Project lists what a container splits:
- Separated: cookies, localStorage, IndexedDB, the HTTP cache and the image cache.
- Not separated yet: history, bookmarks, and exceptions for invalid TLS certificates.
- Not separated, on purpose: saved passwords, saved search and form data, HSTS flags and OCSP responses.
What Firefox profiles separate
A Firefox profile is a separate folder of user data. Mozilla says profiles separate bookmarks, passwords, settings, add-ons, history, and browsing data such as cookies and logins.
Firefox now has a built-in profile switcher under the account icon in the toolbar. It first appeared in Firefox 138. Firefox 150, in April 2026, made it available to all desktop users, including on Windows 10. It is not on Android or iOS. The older about:profiles page still works. Two details from Mozilla’s page matter for privacy:
- Your “Data Collection and Use” settings apply to every profile on the device.
- You cannot sign in to one Mozilla account in two profiles on the same device.
Containers vs Firefox profiles vs AliasMode profiles
| What | Firefox containers | Firefox profiles | AliasMode profiles |
|---|---|---|---|
| Cookies | Separate | Separate | Separate |
| Local storage and IndexedDB | Separate | Separate | Separate |
| HTTP and image cache | Separate | Separate | Separate |
| History | Shared | Separate | Separate |
| Bookmarks and saved passwords | Shared | Separate | Separate |
| Extensions | Shared | Separate | Separate |
| HSTS flags and certificate exceptions | Shared | Separate | Separate |
| Canvas | Your device’s output, with noise per site and container since Firefox 151 | Your device’s output, with noise per site and session since Firefox 151 | Per-profile noise in AliasMode Chromium |
| WebGL, fonts, screen, user agent | Same | Same | Per-profile values |
| IP address and proxy | Same IP; the extension can set a proxy or Mozilla VPN location per container | Same IP; each profile can set its own proxy | Own HTTP or SOCKS5 proxy per profile; WebRTC stays on the proxy path |
| Timezone and language | Your computer’s | Your computer’s | Set to match the proxy’s exit location |
Fingerprint, IP and timezone: what neither feature changes
Can a site link two containers to one person? Not through cookies. Through the fingerprint and the IP address, often yes. Both containers report the same browser version, fonts, screen size, GPU and timezone. A fingerprinting script sees one device with two logins. Two Firefox profiles look the same way.
Multi-Account Containers can send each container through its own proxy or a chosen Mozilla VPN server. Mozilla’s support page says this needs a Mozilla VPN subscription. It does not work in Snap or Flatpak installs of Firefox.
A per-container VPN location can create a mismatch. The timezone still comes from your computer. A container that exits in another country still reports your home timezone.
When to use containers, profiles or something else
| You want to | Use |
|---|---|
| Log in to two accounts on one site, side by side | Containers |
| Keep separate extensions, passwords and history for work and home | Firefox profiles |
| Give each identity its own IP address | A proxy per container or per profile |
| Make two identities look like two devices | Separate devices, or profiles with their own fingerprint values |
| Blend into a crowd and hide your IP address | Tor Browser, or Mullvad Browser with a trusted VPN |
Tor Browser and Mullvad Browser are the right tools for anonymity. They give every user the same values. Containers and profiles do a different job: they keep several known identities apart.
Where AliasMode fits
AliasMode is a free, open-source profile manager for Windows, Mac and Linux. Each profile has its own data folder, proxy, and stable fingerprint values. Timezone and language follow the proxy’s exit location. It fits when you keep a few long-lived identities that should not look like one device.
Frequently asked questions
Do Firefox containers protect against fingerprinting?
No. Every container runs in the same Firefox on the same computer, so fonts, screen, GPU, user agent and timezone match. Since Firefox 151, canvas readouts carry small noise that differs per container. The other signals still match.
Are Firefox profiles more private than containers?
Profiles split more stored data, including history, saved passwords and extensions. They do not change the fingerprint or the IP address. To a site that fingerprints, two profiles look much like two containers.
Do Firefox containers share history and passwords?
Yes. Mozilla’s wiki lists history and bookmarks as not separated yet. It lists saved passwords, form data, HSTS flags and OCSP responses as shared on purpose.
Can each Firefox container use a different IP address?
Yes, with the Multi-Account Containers extension. Set a proxy per container, or a Mozilla VPN location per container with a Mozilla VPN subscription. The timezone still comes from your computer.
Can I use containers inside a Firefox profile?
Yes. Containers work in any profile. Mozilla notes that the extension and its containers are not shared across profiles. Set them up in each profile.