Two Firefox profiles open at once on a Mac
Can you run two Firefox profiles at the same time on a Mac?
Yes: Firefox's profiles keep sign-ins, cookies and extensions apart, and Firefox can run two at once. Parallex turns a profile into something you open on its own: Firefox started with a profile folder of its own, from Parallex, the menu bar or a shortcut, its windows outlined in its color, with the links you choose sent to it.
Keep a work Firefox beside your own as a separate instance: its own profile, sign-ins, cookies and extensions, opened from Parallex, the menu bar or a shortcut, its windows outlined in its color.
How
- Install Parallex (below). Your Firefox isn't changed.
- Choose New Instance and pick Firefox. Name it for what it's for, like “Firefox Work”, and give it a color.
- Open it and sign in with the other account. Both run at once, each in its own windows, outlined in the instance's color.
Or without Parallex: every way to run an app twice on a Mac, compared.
What you get with Firefox
- Its own profile folder: Parallex starts Firefox with a profile folder of its own, so its sign-ins, cookies, history and extensions are separate from your Firefox's.
- Window outlines in its color, and its name in the menu bar, so you can tell the two apart at a glance.
- Opened on its own: from Parallex, the menu bar, the ⌃⌥Space switcher or a keyboard shortcut of its own.
- Links to the right browser: send links from other apps to the instance, with rules per site.
- Own identity, when you want it: a copy of Firefox with its own Dock icon, notifications and macOS permissions, which Parallex keeps up to date. The lab tries this copy every night too.
Tested every night
Parallex's compatibility lab makes a fresh instance of Firefox 155.0.1 (the app itself, opened with a profile folder of its own, as New Instance makes it) every night on a clean Mac and opens it. On October 4, 2026, on macOS 26.6.2, it ran, and nothing reached the original's data. Its instances have run clean on all 2 nights since October 3. Made as its own copy instead (Own identity), it ran clean too. See every app's latest result.
Good to know
- The instance is Firefox itself, so it shares Firefox's Dock icon unless you turn on Own identity; its windows are outlined in its color instead.
Questions
Firefox already has profiles. Why this?
Profiles are the right tool, and Parallex uses them: an instance is Firefox started with a profile folder of its own. What it adds is a way to open that profile on its own, tell its windows apart, and send links to it.
Can I do it in Terminal instead?
Yes: open -n -a Firefox --args --no-remote --profile <folder> starts a separate Firefox with that profile. Parallex does the same thing, with a name, a color and a shortcut.
Get Parallex
Free to try, for macOS 14 and later. In Terminal:
curl -fsSL https://parallex.mandip.dev/install | shOr download the disk image, or with Homebrew: brew install --cask mandipadk/parallex/parallex. Then choose New Instance, pick Firefox, and give it a name.
Already have Parallex?
This opens New Instance with Firefox picked; you name it and choose its color.
Make a second Firefox