Run a second copy of any Electron app.
A second Claude, a second Slack, a second Discord, each with its own login, settings, and Dock icon. The original app stays untouched and keeps updating itself.
Three lines, no Gatekeeper warnings.
brew tap bnimit/tap brew trust bnimit/tap brew install --cask duplex
brew trust is a one-time step Homebrew asks for on third-party taps. Prefer a direct download? Grab the notarized zip from the latest release. Requires macOS 13 or later.
A login for every copy
Each instance keeps its profile, cookies, and settings in an isolated data folder. Two accounts, zero collisions.
The original stays untouched
Wrappers launch the app's own binary with an isolated profile. No patching, no re-signing, updates keep flowing.
Logins that actually work
OAuth callbacks route to one app on macOS. Duplex's link routing sends them to the instance you are signing in to.
Small and inspectable
Native Swift, zero dependencies, notarized by Apple. The source is public on GitHub under a source-available license.