The major competitors include Fabric and Forge, with each being distinguished primarily by the type /amount of extensibility they offer. Paper is focused on "ba

The major competitors include Fabric and Forge, with each being distinguished primarily by the type /amount of extensibility they offer. Paper is focused on "backend only" modding (plugins), as opposed to the "full spectrum" modding supported by Fabric and Forge that often (but not always) require users to download the mods on their computer as well. From that perspective, Paper is much more commonly used by commercial server owners (since they're catering to the very large audience of casual users who don't want to install mods) and casual users paying for a server host for their friends who just want a couple of small tweaks, while Fabric and Forge are generally used more by smaller groups of dedicated power users who want a lot of extra mods Paper and Forge both focus primarily on providing a large extension API through modifying the decompiled Minecraft source code, while Fabric takes a different route by providing primarily an extensive dynamic Java bytecode modification library that allows developers to effectively "build their own API" by modifying the vanilla Minecraft classes at runtime. This means Fabric is generally much faster and easier to update to newer versions, and most smaller mod developers have adopted it as their preferred platform of choice due to the more powerful tools, and use open source libraries to make up for the lack of a built in API. (These are generalizations, of course, and Forge and Fabric have experienced a fair amount of convergent evolution at this point as well.) On the performance side, there's a new experimental Paper-like server called Folia from some of the core developers aimed at providing radical parallelism. Normally, all Minecraft servers run their main gameloop on a single thread, and the largest of server operators deal with the issue by providing front end proxies that shard users to different servers, which limits interactivity. From a technical complexity level, you could almost compare it to a GIL-less server reimplementation. All, again, built as patches onto the decompiled Minecraft source code. It's gaining more stability and has been used in some very exciting public tests