ResusSim is in closed beta: create an account and accept the beta terms, and the downloads unlock here as soon as the team approves you. One computer in the room hosts the simulation; every tablet, phone and laptop just joins it.
Detected:—
One computer hosts. Everything else joins.
You only install ResusSim on the host — a Mac or Windows PC. The bedside iPads, student phones, a wall TV and any laptops connect to it over your room’s Wi-Fi with nothing to install.
Create a beta account — accepting the beta terms (confidentiality/NDA, no reverse engineering) — and the ResusSim team approves each tester. Your account then unlocks the downloads here and signs you in inside the app.
Downloads unlocked. Signed in as — use the same email and password inside the app. Sign out
v0.1.0-alpha.1 · free early access · not sure which? Apple menu ▸ About This Mac — “Apple M…” means Apple Silicon
Open the downloaded ResusSim.dmg and drag ResusSim into your Applications folder.
Open it from Applications. The first time, macOS shows “Apple could not verify ‘ResusSim’ is free of malware.” — this is expected (see the note below).
Do not click “Move to Bin” — on recent versions of macOS that is the blue, default button. Click Done.
If your dialog offers Open Anyway right there, click it and skip to step 5.
Go to Apple menu ▸ System Settings ▸ Privacy & Security, scroll to the Security section. You’ll see “ResusSim was blocked to protect your Mac.” Click Open Anyway.
“ResusSim” was blocked to protect your Mac.
macOS cannot verify that this app is free from malware.Open Anyway
Confirm with Open Anyway once more and enter your Mac password or Touch ID. ResusSim launches.
macOS then asks “Do you want the application ‘ResusSim’ to accept incoming network connections?” — you must click Allow.
Do you want the application “ResusSim” to accept incoming network connections?
This one matters more than the warning above. ResusSim runs the simulation on this Mac and your tablets and phones connect to it over the Wi-Fi. Clicking Deny lets the app open normally, so nothing looks wrong — but no device will ever be able to pair, and the failure shows up later as a QR code that never connects.
Clicked Deny already? System Settings ▸ Network ▸ Firewall ▸ Options, find ResusSim and set it to Allow incoming connections.
Why the warning? ResusSim is in early access and isn’t yet registered with Apple’s notarization service, so macOS asks you to approve it by hand the first time — the same one-time step used for many trusted apps from small developers. Nothing about the app is unsafe; the registration is simply a step we complete before general release, and once it is done this screen disappears (on most Macs the network prompt does too, since macOS lets registered apps through automatically).
You’ll do this again on the next update. Each early-access build carries its own seal, so macOS treats a new version as a new app and asks once more. It is the same two clicks, and it stops for good once we complete Apple’s registration.
Seeing “ResusSim is damaged and can’t be opened”? That means you have a build downloaded before 20 July 2026. Delete the app and the old .dmg, re-download from this page, and install again — the current build shows the normal “could not verify” dialog above instead.
Windows shows a blue “Windows protected your PC” screen. Click the small More info link, then the Run anyway button that appears.
Windows protected your PC
Microsoft Defender SmartScreen prevented an unrecognized app from starting.
If Windows asks to allow changes (User Account Control), click Yes. The installer sets everything up, including the firewall permission the devices need — no extra prompts.
ResusSim opens automatically. Future launches skip the warning on this PC.
Why the warning? Same reason as on Mac: the app isn’t yet code-signed for wide release, so SmartScreen flags it as “unrecognized” the first time. More info ▸ Run anyway is the standard one-time approval; it disappears once we add the signing certificate before general release.
iPad, Chromebook, phone or laptop nothing to install
These devices don’t host — they join the Mac or PC that does. Just open a browser.
✓On the host, start a session — it shows a room code and a QR code.
✓Scan the QR with the device’s camera, or type the room’s web address into Safari or Chrome.
✓The device lands on the right screen — bedside monitor, EMR, consult phone or CPR tool — and stays in sync over your Wi-Fi.
Planning to use live call audio, a phone as the CPR/BVM sensor, or the in-room recorder? Those need one extra one-time step per device — the Secure mode manual walks through it for iPhone/iPad, Mac, Windows and Chromebook.
Chromebooks can’t be the host — they have no way to run the installer — but they make excellent joining screens. Keep the host on a Mac or Windows PC, and let Chromebooks, iPads and phones connect to it.
System requirements
✓Host — Mac: macOS 11 Big Sur or newer · Apple Silicon (M1–M4) or Intel.
✓Host — Windows: Windows 10 or 11, 64-bit.
✓Joining devices: anything with a current browser — Safari or Chrome from roughly the last three years. iPads, iPhones, Android, Chromebooks, laptops, smart-TV browsers.
✓Bedside monitor & ventilator displays: the live waveforms want recent silicon — iPads from ~2020 on (A14/M-series) render them cleanly; older iPads (2018 and earlier) show visibly rough traces. Older tablets still work fine as the EMR, pumps or phone.
✓Network: any Wi-Fi the host and devices share — room Wi-Fi, a dedicated router, or a phone’s hotspot. Internet is only needed to download the app and for AI scenario generation, never mid-session.
