Works good. I found it a couple weeks ago. Not an advertisement or promotion. I am just sharing because it took me a decent bit of time to find a web app that could efficiently draw rectangular rooms and other common architectural features such as windows and doors. Canva sucks at this by comparison and I didn't want to buy an offline cad program that had gratuitous complexity and resource requirements to just do a simple task.

It would be cool if someone could duplicate this functionality as an offline tool that was also scriptable / had a command line interface. I woukd base it on a database where each element (eg wall), room, etc was its own record with various parameters as fields in the record. Output for external sharing would be as SVG or PDF.