A "missing dependency" error is one of the more beginner-friendly crashes a modded server can throw, because the log almost always names the exact mod it is looking for. The fix is usually just finding and adding it correctly.
Step 1: Read the exact error
Open logs/latest.log or the crash report and look for a line naming the missing mod, something like requires {fabric-api} or Missing or unsupported mandatory dependencies. Forge, NeoForge, and Fabric all report this differently in formatting, but all three name the specific mod ID that is missing.
Step 2: Find that dependency on the same platform
Search for the named mod on Modrinth or CurseForge. Common dependencies include:
- Fabric API — required by most Fabric mods.
- Cloth Config — a shared settings-menu library several mods rely on.
- Architectury API — used by mods that ship versions for multiple loaders from one codebase.
- A specific library mod the main mod's author publishes separately (check the main mod's page, dependencies are usually listed explicitly).
Step 3: Match the version and loader exactly
Download the dependency for the same Minecraft version and the same loader (Forge, NeoForge, or Fabric) as the mod that needs it, and as your server itself. A dependency built for the wrong loader will not satisfy the requirement even if the mod ID matches.
Step 4: Add it and restart
Drop the dependency's jar into the mods folder alongside everything else and restart. If the error is gone, that was the whole fix. If a new missing-dependency error appears for a different mod, repeat the process, dependency chains (a dependency that itself has a dependency) are common with larger mods.
If the dependency doesn't seem to exist for your version
This usually means the main mod has not been updated to support that Minecraft version yet, even if the mod itself appeared to support it. Check the mod's own version history for confirmation before assuming you are searching for the wrong thing.
A quick sanity check afterward
Once the server starts cleanly, confirm the fix actually stuck by checking the loaded-mods list in the log rather than assuming, occasionally a dependency loads but at a version too old for what the main mod actually needs, which throws a different, more specific error on the next restart.
Avoiding this going forward
Checking each mod's listed dependencies before adding it, not after it crashes, saves a lot of this back-and-forth. Tick Hosting's panel shows startup errors directly in the live console, so spotting a missing dependency takes seconds instead of hunting through log files. Available on every plan, including the free tier, from Tick Hosting's plans page.