We build small, sharp tools for people who expect their Mac to keep up with how they actually work.
See the work →run two of every app on one Mac, each with its own login.
Each Duplex instance keeps its own profile, cookies, and settings in an isolated data folder. Two accounts, zero collisions.
Learn moreDuplex never modifies the target app. Wrappers launch the app's own binary, so updates keep flowing exactly as before.
Learn moreRead the code, audit it, build it for yourself. The full source, tests, and build script are public on GitHub.
Read the license* tools that earn their place in the Dock.
Run a second copy of any Electron app, with its own login.
The next tool is in progress. One at a time.
Tell us the small Mac problem you hit every day.
A tool should do one job completely rather than ten jobs halfway. Duplex duplicates apps. That is the whole job.
Plain Swift on native frameworks. Nothing to vendor, nothing to rot, nothing phoning home.
A $5 license, unlimited instances, up to 3 Macs. The first instance is free forever, no trial clocks.