Thanks! The entire project essentially lives in a series of horizontally scaling node.js processes doing all kinds of things. The worlds are divided into chunks which helps significantly with culling network traffic and distributing the load.

For the database I moved from MongoDB to Postgres. When I started doing Hordes I had very little DB experience and thought that using MongoDB might be a good idea since I am using node. Turns out that Postgres is much better at helping with transactional logic for an MMORPG. Inventory management for example can be constructed almost entirely with constraints, ensuring that the data always makes sense (no two items occupying one slot, that kind of thing).

The alpha used vanillajs for the entire front end, but with the beta I started using Svelte and Rollup, which I would highly recommend for almost anything.