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Join from another device

Open the same Moonshine session on a phone, tablet or laptop so you can align from where the projection actually lands.

Any device on the same network as the show computer can join. It runs the same interface, sees the same project, and counts as another user in the session — including its own locks and its own presence marker.

Open the Share dialog

In the top bar, click the QR code button (its tooltip reads Share / connect a device). The Share Moonshine dialog opens. Close it with the Esc control in its top-right corner, the Esc key, or a click outside it.

The dialog gives you three ways to get the address onto the other device:

  • Scan the QR code with the device's camera.
  • Copy the address and send it however you like. The button changes to Copied for a moment when it works.
  • Read it out — the address is in the field next to the button; clicking the field selects the whole thing.

Two addresses, one session

Depending on how the show computer is set up, the dialog offers up to two addresses. They reach the same session and the same project — the difference is only whether the device is allowed to show live video.

Address What works Setup needed on the device
Secure address (the one on the QR code, offered as Join) Everything, including the live video preview A one-time certificate install — see below
No-setup option (control only, no video) — shown in small text underneath Everything except the live video preview None

The second address is worth knowing about. If someone just needs to trigger playback or nudge a corner and does not need to see the video feed in their own browser, hand them that one and skip the setup entirely.

If the show computer has no secure address available, the dialog drops the two-tab layout and shows a single QR code with the line Scan to open Moonshine on another device on this network. That address behaves like the no-setup one: everything works except the live video preview.

Why the video preview needs the secure address

Browsers only allow live video decoding on a connection they consider trusted. The plain address is not one, so on that address the interface works but the video panes stay empty. Nothing else is withheld.

If the show computer has no network address to share, the dialog says so in amber: the link shown will only work on that machine. Put the show computer on the same network as everyone else, then reopen the dialog.

First-time setup on a new device

A device that has never joined before needs the Moonshine certificate installed once before the secure address will show video. In the Share dialog, switch to the First-time setup tab — the QR code changes to point at the setup page, and the caption reads Scan on a new device to install the Moonshine certificate (one-time). Then switch to Join.

Scan that code on the new device. The page that opens is titled Enable video preview on this device and has one button, Download certificate, followed by instructions for each platform. Do the download first, then follow the steps for your device.

  1. Tap Download certificate. Safari asks to allow a configuration profile — tap Allow.
  2. Open Settings → General → VPN & Device Management, tap Moonshine Local CA, then Install (top right) and enter your passcode.
  3. Do not stop there. Go to Settings → General → About → Certificate Trust Settings and turn ON the switch for Moonshine Local CA. Until you flip this switch the certificate is installed but not trusted, and video still will not appear.
  4. Return to Moonshine and reload the page.

iOS 18.0–18.1

Those two releases had a bug where the certificate never appears under Certificate Trust Settings. Update to iOS 18.2 or later if you hit it.

  1. Tap Download certificate.
  2. Go to Settings → Security & privacy → More security settings → Encryption & credentials → Install a certificate → CA certificate, then pick the downloaded file. Choose CA certificate — not the VPN or app option.
  3. Reload Moonshine in Chrome.

Android shows a permanent "Network may be monitored" notice for any user-installed certificate. That is expected and does not mean anything is wrong.

  1. Download the file, then double-click it → Install Certificate → Current User → Place all certificates in the following store → Trusted Root Certification Authorities → Finish.
  2. Fully restart the browser — not just the tab.
  1. Download the file and double-click it. Keychain Access opens. Find Moonshine Local CA in the System (or login) keychain.
  2. Double-click it, expand Trust, set When using this certificate to Always Trust, then close the window and enter your password.
  3. Reload Moonshine.

Firefox keeps its own certificate store, so the OS-level steps above do not cover it — on any desktop operating system, do this instead:

  1. Settings → Privacy & Security → Certificates → View Certificates → Authorities → Import, choose the downloaded file, and tick Trust this CA to identify websites.
  2. Reload Moonshine.

Firefox scopes per-site exceptions by port, so importing the certificate is the only reliable way to cover both the interface and the video stream.

Once the certificate is in place, switch the Share dialog back to Join, scan that QR code (or open the secure address), and sign in. The video preview appears.

Signing in on the joined device

Joining does not sign you in. The device lands on the same sign-in screen as the show computer and needs an account.

One account, one session

Signing in with the same account on a second device ends the first one. The device you left behind returns to the sign-in screen with Signed in from another tab. Please sign in again to continue here. If two people are working at once, give them separate accounts — see Users and sessions.

If it does not work

Symptom Likely cause
The QR code opens a page that never loads The device is on a different network from the show computer — a guest Wi-Fi network, or mobile data instead of Wi-Fi
The interface loads but the video panes stay empty The device is on the no-setup address, or the certificate step was not finished. On iPhone, check the Certificate Trust Settings switch specifically
It worked yesterday and not today The show computer's address changed. Reopen the Share dialog and scan the current code
The dialog warns there is no network address The show computer is not on a network the other devices can reach

Next: Tour of the interface.