Hey thanks for the checking Moddio out! There are a bunch of free multiplayer features such as netcode and server orchestration, and social features like moderation and in-game chat. So all the backend tech is already included with every game. Single player games are still possible, but having all the aforementioned built in features makes multiplayer games really easy to make.
Co-founder here. Additionally, you are able to set different stream mode for each entities and script actions which allows you to customize your players’ multiplayer experience. For example, doing a lag compensation by syncing player unit positions (between server and client) but not rotation nor bullet positions
The games are hosted on our bare-metal servers, but you do have the option to self-host games as well. Our engine is open source (https://github.com/moddio/moddio2)