Open your server in the panel and use the Plugins tab to search and install with one click. It picks versions that match your server.
- Pick the plugin or mod and press Install.
- Restart the server from the Console page.
Plugins need a plugin server type (Paper, Purpur, Spigot). Mods need a mod loader (Fabric, Forge, NeoForge). You can change the server type in Settings → Change game.
To install something by hand, upload the .jar into the plugins (or mods) folder in the Files tab, then restart.