Minecraft custom commands without plugins
You can add custom commands to a Minecraft server without installing a plugin. Vanilla Minecraft already runs data packs. Here is what that gets you.
What a data pack can do
A data pack is a folder of functions the game runs itself: give an item, run a command, show a title, check a score. Because it is vanilla, it works on a normal server, a Realm or a single-player world.
Where a data pack stops
Data packs run when the game asks them to, so they cannot do everything a plugin can: some events never reach them, and anything that needs a server-side library is out. That is why each Elementium element says whether it works as a data pack: yes, partly, or no.
Build one
Pick the elements you want, wire them, and check the data pack column on each. When everything says yes or partly, export the flow as a data pack and drop it into your world's datapacks folder.
When you do want the plugin
If an element says no, or you want things like ranks tied to a permissions plugin, use the Elementium plugin on a Paper server instead. Both come from the same flows.
Questions
Do custom commands need a plugin?
Not always. Data packs can add functions and many commands on a vanilla server.
Will every Elementium flow work as a data pack?
No. Each element is marked yes, partly or no, and the editor tells you the difference.