I just had a jaw-drop moment – Termux allows you to install NodeJS on an Android device!
It seems to work for a basic Websocket Speed Test I had on hand. The http served by it can be accessed both locally and on the network.
There is a medium post that explains the installation process
Basically:
1. Install termux
2. apt install nodejs
3. node it up!
One restriction I’ve run into – it seems the shared folders don’t have the necessary permissions to install modules. It might just be a file permission thing. The private app storage works just fine.