Install plugins and mods

This section doesn't exist for Vanilla servers — Vanilla doesn't run plugins or mods, so the tab is hidden entirely (it's also hidden briefly while a server is still installing). Everywhere else, it's labeled Plugins on Paper and Purpur cores, and Mods on every other core regardless of what that core actually loads — same section, just a different label.

Searching and installing from the catalog

Type into the search box to search the catalog — Modrinth by default; some deployments also offer CurseForge, shown as a switcher above the search box when available. Search kicks in at two characters and always runs, whatever your core or the selected platform. Results are filtered to what your core can actually load only on Modrinth, and only for Paper, Purpur, Forge, NeoForge, and Fabric; everywhere else — including a Fabric server searching CurseForge, which only narrows by plugins-vs-mods rather than by loader — results aren't scoped to your core, so check compatibility yourself before installing. On a Paper, Purpur, Forge, NeoForge, or Fabric server searching Modrinth, category chips (management, economy, optimization, adventure, social, utility) let you browse without typing anything. If a search comes back degraded — the catalog's own search is down — the panel says so and falls back to an exact-name match instead of full results.

An item already installed on your server shows Installed instead of Add. Clicking Add installs the newest version the catalog currently offers for it — there's no version picker in this flow, so every catalog install is unpinned. For a Modrinth install specifically, that means the latest build compatible with your server is what actually gets installed each time the server starts, not a version frozen at install time. Don't expect a catalog install to stay on a specific version; if you need that, upload the jar yourself instead.

Uploading your own .jar

Upload .jar is hidden on Vanilla and on any server set up from a modpack (a modpack's manifest already controls its jar list) — everywhere else the button shows. What actually accepts a jar underneath is narrower than that: only Paper, Purpur, Fabric, Forge, and NeoForge servers can. On any other core — a Velocity proxy, for instance, which has its own real jar-based plugin ecosystem — the button can still appear, but the upload fails with "this server type can't load plugins or mods". That's this platform's own restriction, not a statement about what the core supports: uploaded jars are currently only accepted for those five cores. The upload has to be a real .jar/zip archive, and is capped at 100 MB. An uploaded jar is yours — it doesn't change on its own the way a catalog install can; updating it means removing the old one and uploading the new file.

Removing an install

Remove uninstalls the plugin or mod, but keeps its config files on the server — so reinstalling it later (or upgrading it) doesn't lose whatever it was configured to do.

When changes actually apply

Installs, removals, and uploads all apply the next time the server starts or restarts — never immediately, and there's no separate "apply now" step. If you just changed something and nothing looks different, that's expected until the next start.

Troubleshooting

Don't see this section at all. Either the server is Vanilla (plugins/mods aren't supported there) or it's still finishing installation.

Don't see Upload .jar. Same two cases as above, plus: the server was created from a modpack, whose jar list is managed by the modpack instead.

Upload .jar is there, but every upload fails with "this server type can't load plugins or mods". See "Uploading your own .jar" above — the button's visibility is broader than what this platform actually accepts.

Search or Add fails. If the panel can offer an alternative — the other catalog platform, or uploading the jar directly — it says so under the error. Otherwise retry; a catalog outage on the upstream side is possible and not something a retry on our end fixes.

Installed something and the server behaves the same as before. Restart it — installs only take effect on the next start, not the moment you click Add.