Minestom is an alternative to the popular minecraft server API named Bukkit/Spigot. The main difference is that our implementation of Notchian server does not contain any features by default! However, we have a complete API which allows you to make anything possible with current spigot's plugins.
Minecraft evolved a lot since its release, most of the servers today do not take advantage of vanilla features and even have to struggle because of them. Our target audience is those who want to make a completely different server compared to default Minecraft gamemode such as survival or creative building.
The goal is to offer more performance for those who need it, Minecraft being single-threaded is the most important problem for them.
It is our major concept, worlds are great for survival with friends, but when it scales up it can become unmanageable. The best examples can be found in Skyblock or minigames, not being able to separate each part properly and being forced to save everything in files, not to say the overhead caused by unnecessary data contained in them. Instances are a lightweight solution to it, being able to have every chunk in memory only, copying and sending it to another player in no time, making your serializer and much more...
Instances also come with performance benefits, unlike some others which will be fully single-threaded or maybe using one thread per world we are using a set number of threads (pool) to manage all chunks independently from instances, meaning using more of CPU power.
Minestom by default does not know what is stone block, not even a chest, you will have to tell him that it opens an inventory. Every "special blocks" (which aren't only visual) have to be registered, then they can be placed anywhere simply.
The terms "passive" or "aggressive" monsters do not exist, nobody forbid you from making a flying chicken rushing into any players coming too close, doing so with NMS is a real mess because of obfuscation and the large inheritance.
It is a field where Minecraft evolved a lot, inventories are now used a lot as client<->server interface with clickable items and callback, we support it natively without the need of programming your solution.
Commands are the simplest way of communication between clients and server. Since 1.13 Minecraft has incorporated a new library denominated "Brigadier", we then integrated an API meant to use the full potential of args types.
