macOS & Windows · multi-instance launcher

Run two of everything.

Twindow runs a second, fully isolated copy of the apps you already use — each with its own account, data, and Dock icon. Two Claudes. Two Chromes. Two Slacks. One Mac.

Download See how it works

Free · macOS now, Windows soon · no account, no telemetry

Two of anything. Stay signed into both at once.

Chrome · profilesWhatsApp · 2 numbersVS Code · per-clientClaude · work & home

What it does

A second instance, not a second window.

macOS lets you run an app once. Twindow gives each copy its own private home — separate logins, separate history, separate everything — while the original app stays exactly as it was.

Truly separate data

Each clone gets its own data home, so two accounts stay logged in side by side — no more signing out to switch.

It figures out how

An auto-detection engine probes each app and picks the right isolation for it — instead of a hand-maintained list of “supported” apps.

Not just apps

Clone an app, pin a website as its own isolated WebKit app, or turn a file or command into a Dock launcher — four shortcut types.

Tell them apart

Draw a WORK or DAY label right on the icon, and add an optional menu-bar icon per instance.

Yours, and private

No telemetry, works offline, and it never modifies or re-signs the original app — it stays signed, trusted, and auto-updatable.

Native & light

A real macOS app — notarized, auto-updating. Each clone is a ~2 MB launcher, not another full copy of the app.

How it works

Three steps. Under thirty seconds.

No terminal required — though there’s a full CLI when you want one.

Pick an app

Browse the apps on your Mac. Twindow reads each one and suggests how to isolate it.

Name the clone

“Claude (Work)”. Add a label badge, a custom icon, or a menu-bar icon if you like.

Launch

A new app appears in ~/Applications, ready to pin to the Dock and run alongside the original.

zsh — twindow

# prefer the terminal? one line does it too
$ twindow create --app /Applications/Claude.app --name "Claude (Work)" --label WORK
  → created ~/Applications/Claude (Work).app — open it.

Built to be trusted

Honest about what it can — and can’t — do.

Twindow works beautifully for the apps most people run every day. And where macOS makes true isolation impossible, it tells you up front instead of pretending.

Works cleanly

Non-sandboxed appsSlack, Chrome, VS Code, browsers, Electron & more

Auto-detected

Chromium · Firefox · Eclipseget the right data-dir automatically

Footprint

~2 MB per clonea launcher, not a second copy

Updates

Notarized · auto-updatesigned and delivered via Sparkle

Sandboxed Mac App Store apps are the exception: macOS pins their data to a protected container that no tool can redirect. Twindow still gives them a separate Dock icon, and flags the limit clearly at create time — no silent data-sharing.

Get Twindow

Two of everything.
One download.

Free and native. macOS ships first; a Windows build is in development.

macOS

DownloadmacOS 13+ · Apple silicon & Intel

Windows

In development soonWindows 10 & 11

On macOS, you confirm the first launch — Twindow is a free, un-notarized app, not malware. Here's how (10 seconds) →

Installing on macOS

First time you open it

Twindow is a free, independent app. It isn't run through Apple's paid notarization program, so macOS asks you to confirm the very first launch. It's safe — here's the 10-second version.

1
Move it to Applications
Open the downloaded .dmg and drag Twindow into your Applications folder.
2
Approve it once
macOS Sequoia (15): open System Settings → Privacy & Security, scroll down, and click Open Anyway next to Twindow.
macOS Ventura / Sonoma (13–14): right-click Twindow in Applications → Open → Open.
3
That's it
It opens normally every time after that — and updates itself from then on.