GMPulse

GMPulse is a GameMaker extension that makes it possible to manipulate information about your game while it's running. Monitor and update variables, change rooms, toggle fullscreen, and more. Enable speedy prototyping without the need to restart your game every time you want to change a single variable.

It features an external web-based GUI that serves a "command center" for your game. Access it on your computer, your phone, or any other device on your network.

This is a zero-setup extension that is fully functional just by adding it to your project. Drag the extension in, and you're immediately ready to go.

View the extensive online documentation here.