They only work for Java Edition. As for competitors...well it is not really a competition -- it just depends on what you are focused on for your player-base. P

They only work for Java Edition. As for competitors...well it is not really a competition -- it just depends on what you are focused on for your player-base. Paper is a performance-focused fork of Spigot which is an, to very loosely describe, "interface" for Bukkit. Bukkit itself is an API for Minecraft that interfaces with plugins/mods. If someone is running "modded" Java Minecraft, they are likely touching one of these, or even a fork of Paper. Paper adds some features/tweaks on-top of Spigot and if your server is having some performance issues or you want a specific feature that Paper offers then you would utilize Paper. If you are fine on Spigot, you use Spigot. Personally I have always used Paper when hosting servers, as performance (less "rubber-banding" with higher player-counts) was my focus in that time. As well Paper offered the configurable option of "per-player" mob spawning, so we did not have a single player that stood above a cave hogging all of the mob spawns.