Use Two Accounts on One Website with Firefox Containers

Signing out of a website just to check a second account gets old quickly. Firefox Multi-Account Containers lets you keep those accounts open side by side: put one in a Personal container and the other in Work. Each container has its own cookies, so the website can maintain a different sign-in in each. Mozilla introduced the extension in September 2017 .

This guide covers the desktop extension and its documented controls as of 16 April 2026. Start with two containers and choose them manually; automatic site assignments need a little more care when both accounts use the same address.

What a container changes

A container gives websites a separate slice of browser storage. Opening your usual email site in a new container does not bring its existing sign-in cookies along. You sign in again there, using the account you want that container to hold. Opening two ordinary tabs in the same container still uses that container’s shared website session. Mozilla’s containers project documentation explains this storage separation.

For example, imagine you manage a personal account and a club account on the same service. Name two containers Personal and Club, then open the service separately in each. Before posting a message, check the account name shown by the service as well as the container label. The label helps you organise the tabs; it cannot check whether you entered the intended credentials.

Open the two account sessions

Use a normal Firefox window. Containers are unavailable in Private Browsing and when Firefox is set to Never Remember History.

1. Visit Mozilla’s Firefox Multi-Account Containers listing , select Add to Firefox, then review and accept the permissions if you want to proceed.
2. Open the Containers toolbar button. If it is hidden, find it under the Extensions button.
3. Choose Personal, visit the service and sign in to your first account.
4. Open the Containers button again, choose Work, and visit the same service. Sign in to your second account.
5. For a custom name, use Manage Containers. Choose New container to add another.

These controls are documented in Mozilla’s October 2025 support revision .

The permission request can look broad. Mozilla explains that website access lets the extension intercept requests when reopening sites in assigned containers, while tab access helps it choose where a page belongs. Read the permission explanations before installing, particularly on a browser you use for sensitive work.

Check that the accounts stay separate

Use this small check before relying on the arrangement:

1. In Personal, open the service’s account menu and confirm the first account’s name or email address.
2. Switch to Work and confirm the second account there.
3. Reload each tab, then check both account menus again.

The result you want is two different accounts still visible in their intended containers. If both show the same account, check the container labels first. You may have opened both tabs in the same container, or signed in with the same credentials twice. Correct that before changing wider browser settings.

Treat this as a check of your setup. A successful result says the two sessions are working for that service; it does not certify the browser’s overall privacy or security.

Be selective with “Always open” assignments

The extension can assign a website to a particular container. Mozilla’s 2017 walkthrough describes how visiting an assigned site from another container brings up a choice about reopening it in the assigned one.

That is convenient for a site you use with only one identity. For two accounts on the same site, it can pull you towards the container holding the other account. Our recommendation is to leave that site unassigned while setting up the two sessions, then add a rule only if it suits your routine.

To remove an existing assignment, open Manage Containers, select the assigned container and choose Manage site list. Hover over the site and use its trash icon. This removes the routing rule; you do not need to delete the whole container. Mozilla documents these controls in the October 2025 revision .

Know what remains shared

Mozilla lists browsing history, bookmarks and saved passwords among the data that containers do not separate. A container therefore does not give someone else using your Firefox profile a private, independent browser space. Its useful boundary here is the website session. Mozilla’s project documentation sets out the distinction.

Containers also leave ways for websites to connect activity. Mozilla’s technical explanation of crossing container boundaries notes that browser fingerprinting remains possible and that URLs can carry identifying parameters. Keeping cookies apart does not make two accounts anonymous to the service operating them.

Once the account checks pass, keep opening each service through its intended container and check the service’s account menu before sending or publishing anything. That habit is what makes the two-session arrangement useful.