01
Not sharing
Screen one
Nothing captured yet
Share two screens
Two screens out. Nothing else.
Pick the two windows or displays your reviewer should see. Your other monitors never leave this machine. Video travels browser-to-browser; nothing is stored.
Session link
Capture a screen to generate your room link.
Your camera
Off. Turn it on to appear in the corner of each shared screen.
02
Not sharing
Screen two
Nothing captured yet
Your pen
Draw on a preview to point something out. Ink fades after 2.5 s. Right-click to leave a sticky note.
Hand over the mouse
Let your reviewer click, type and scroll in the window you're sharing — only that window, and only while the switch is on. Their ink shows up on the real window too, so you see what they're pointing at. Needs the DuoCast Helper running on this Mac: a browser can't move your mouse on its own.
- Download DuoCast Helper (macOS, ~200 KB) and unzip it.
- Open DuoCast Helper. macOS blocks it the first time (it isn't notarised yet): go to System Settings → Privacy & Security, click Open Anyway, open it again. It lives in your menu bar.
- Grant Accessibility when it asks (same settings pane). That's what lets it move your mouse.
This page keeps checking — nothing to refresh.
Reviewer can control screen one
Capture screen one first.
Reviewer can control screen two
Capture screen two first.
Snapshots
Every saved sticky note captures that screen at full resolution, note included. Download the board before you close this tab — it's a single file you can pan and zoom like a Figma board.
01
Capture
Choose exactly two windows or displays. Everything else stays private.
02
Send the link
One URL. Your reviewer clicks once and both screens open as real windows.
03
Draw together
Either side can circle, underline, point. Ink fades so nothing piles up.