It seems the Steamworks API is just a normal Web API. [0] So you probably just need to use fetch() to make requests to it.
For Electron, there is an integration library called Greenworks. For Neutralino, I haven’t found anything similar, so it might be inconvenient to add Steam-specific functionality down the road.
I’m just raising this limitation because it’s one of a few concerns that steered me away from Neutralino for my Steam port project.