Direct answer
Client-only mods run on the player’s machine; server-only mods run on the dedicated server; content mods may need matching installs on both. The author’s documented side support matters more than a mod’s category name.
Recommended procedure
- Open the mod’s official description and release files. Check the supported sides, loader and Minecraft version.
- Client-only examples include many shaders, HUD interfaces and rendering tools; placing these on a dedicated server may cause class-loading errors.
- Server-side-only examples may add server commands, moderation or server optimization without requiring a matching client installation.
- Mods adding items, blocks or networking protocols commonly require a compatible build on both sides. Follow the modpack author’s exact server/client lists.
- If a dedicated server crashes, read for client-only class errors such as
NoClassDefFoundErrorinvolving render classes. If players cannot join, compare the missing-mod or registry messages on both sides.
Why this matters
Minecraft singleplayer runs an integrated logical server inside the physical client, so a mod working in singleplayer does not prove it is safe on a headless dedicated server.
How to verify the result
- Start a real dedicated server with the intended server mod list.
- Connect a test client with the intended client pack; test modded inventory and world features.
- Remove client-only libraries from the dedicated server only after checking they are not required by another server-side mod.
Version and compatibility notes
Important
Do not assume that every performance mod is server-only or that every cosmetic mod is client-only. Some mod authors publish different artifacts for different sides.
Official references
Related guides
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