Download
Windows desktop app. Free, no account needed, works offline.
Needs the .NET 8 desktop runtime and the WebView2 runtime — both are already on most Windows 11 machines, and the installer points you at them if they are not.
Windows SmartScreen will warn about an unsigned installer. That is expected for a fan-made tool without a code-signing certificate — choose More info then Run anyway, or use the source route below if you would rather not.
Start it
Nothing is installed. Node 18 or newer, then open the address it prints.
npm start
Play with friends across the internet
One person in the group hosts the relay once. It is a single file with no dependencies and runs on any free host. Everyone else just needs the party code.
node relay/server.js
Check it before you trust it
The test harness fuzzes thousands of rolls and asserts every claim this site makes about class rules, attachments and challenges.
npm run qa