--- title: "How to Install Mods on a Minecraft Server (Fabric, Forge)" url: https://1up-servers.com/en/blog/how-to-install-mods-on-a-minecraft-server/ lastmod: 2026-10-26 --- # How to Install Mods on a Minecraft Server (Fabric, Forge) Pick Fabric or Forge, install mods from the panel catalogue or upload jars to /mods, set up every player's client and fix the crashes that follow. By [Baurtock](https://1up-servers.com/en/blog/author/baurtock/) Updated Oct 26, 2026 · 8 min read Read in[es](https://1up-servers.com/es/blog/instalar-mods-en-un-servidor-de-minecraft/)[en](https://1up-servers.com/en/blog/how-to-install-mods-on-a-minecraft-server/) **Your game server, free**Ready in 60 seconds, no card.[Create free server](https://1up-servers.com/en/signup/) How to install mods on a Minecraft server: run a mod loader (Fabric or Forge), put the mod `.jar` files in the server's `mods` folder, restart, and give every player the same loader and mods on their own game. Most crashes come from a missing dependency, a wrong game version or a client-only mod on the server. This guide covers Java Edition. If you host with us, everything below happens in the panel of your [Minecraft Java server](https://1up-servers.com/en/minecraft-java-edition/); if you have no server yet, start with our [free Minecraft server guide](https://1up-servers.com/en/blog/how-to-make-a-free-minecraft-server/). Mods use more memory than plugins, so keep our [Minecraft server RAM guide](https://1up-servers.com/en/blog/how-much-ram-minecraft-server/) open as well. - **Loader first:** a mod for Fabric does not run on Forge, and Paper runs plugins, not mods. The template you pick when you create the server decides. - **Fabric API:** the Fabric docs say "the majority of mods require Fabric API as well". Install it like any other mod. - **Same version everywhere:** server, mods and every player's game must be on the same Minecraft version. - **Client side:** players install the same loader and the mods marked for both sides. Client-only mods such as Sodium stay off the server. - **Crash on start:** read the console, find the mod named in the error, remove it from `mods` and restart. ## 1. Pick a loader A mod loader is the server software that loads mods. The [Fabric docs](https://docs.fabricmc.net/players/installing-mods) put the rule plainly: before you install a mod, check that it is "for Fabric and not another mod loader" and for the Minecraft version you play. The same applies the other way round for Forge. On 1up, the loader is the **Template** you pick in the wizard when you create the server. These are the templates production offers for Minecraft Java today: | Template | What it loads | Folder | Mods from the catalogue | Notes | | --- | --- | --- | --- | --- | | Vanilla | Nothing | – | – | It ignores `.jar` files | | Paper | Plugins | `plugins` | Starter and up | Not Fabric or Forge mods | | Fabric | Fabric mods | `mods` | Starter and up | Fits easily in Starter's 4 GB | | Forge | Forge mods | `mods` | Starter and up | The wizard asks for 4 GB of RAM, all of Starter | | Modpack | A whole pack | managed | Pro and up | Fabric, Forge or NeoForge packs, 6 GB | How to choose: - **Fabric** is the lighter option and gets new Minecraft versions quickly. Fabric Loader 0.19.5 is the latest stable build, and Fabric API already has builds for 26.3. - **Forge** is where many older and larger content mods live. Forge's [download page](https://files.minecraftforge.net/net/minecraftforge/forge/) lists builds for 26.3 (66.0.9, no "recommended" build yet) and a recommended 47.4.10 for 1.20.1. Our image installs the recommended build for your version and falls back to the latest when there is none. - **NeoForge** has no template of its own on 1up. NeoForge modpacks install through the **Modpack** template. The version list in the wizard runs from 1.16.5 to 26.3, with 26.3 marked "Latest · recommended". Two older releases, 1.20.1 and 1.16.5, carry the tag "Popular with mods": many big mods stayed on them. Check the mods you want before you pick a version, because every one of them needs a build for it. The panel picks the matching Java version for you. The Bedrock bridge (Geyser and Floodgate) works only with the Paper and Fabric templates, not Forge or modpacks, and only up to Java 26.2. **Minecraft: Java Edition 24/7 from Starter** Your own Minecraft: Java Edition server online around the clock on the Starter plan, €5.00 a month. [Run a Fabric server with mods on Starter](https://1up-servers.com/en/signup/?plan=starter&game=mc-java) ## 2. Upload the mods Mods are `.jar` files in the server's `mods` folder; the [NeoForge server guide](https://docs.neoforged.net/user/docs/server/) says the folder appears after the first start and "is where you want to put your mod files", and [Forge](https://docs.minecraftforge.net/en/latest/gettingstarted/) and Fabric use the same folder. There are two ways to get them there. ### From the panel catalogue 1. Open the **Plugins** tab. On a Fabric or Forge server it searches mods instead of plugins, using the [Modrinth](https://modrinth.com/) catalogue. The header reads "compatible with Fabric 26.3", for example. 2. Search a mod. Each card says "Compatible with 26.3" or "No version for 26.3", so you only see what fits your server's version and loader. 3. Press **Install**. The panel downloads the newest build for your version, checks its signature against Modrinth and puts it in `mods`. 4. Restart the server: the toast reads "Plugin installed · applies on restart". The catalogue does not install dependencies for you. On Fabric, search **Fabric API** and install it first. If a mod's page lists other required mods, install those as well. Installing from the catalogue needs a plan with mods: Free and Casual show "Plugins come with Starter." The **Update all** button later brings every catalogue mod to its newest build for your version. ### By hand: Files or SFTP For a jar you downloaded yourself, for example from CurseForge or a mod's own site: 1. Stop the server, so nothing loads a half-written file. 2. Open **Files**, go into `mods` and press **↑ Upload**, or drag the jars onto the folder. 3. For many files, use **SFTP access** on the same page: generate a password and connect with FileZilla. 4. Start the server. To remove a mod, delete its jar in **Files** (it stays in the trash for 30 days). Only download jars from sources you trust; the Fabric docs name Modrinth and CurseForge. ## 3. Client side A server with mods is only half the setup. Each player needs Minecraft Java with the same loader and the same version: the [Fabric installer](https://fabricmc.net/use/installer/) on Fabric, the installer from the Forge download page on Forge. Their mods go in `.minecraft/mods`; the Fabric docs give the path for Windows (`%appdata%\.minecraft\mods`), macOS and Linux. Which mods go where depends on what each one does. Modrinth labels every project with the environments it supports: | Kind of mod | Example | Server | Players | | --- | --- | --- | --- | | Content: new blocks, items, mobs | most Forge content mods | Yes | Yes, same version | | Libraries | Fabric API | Yes | Yes, when another mod needs it | | Server-side optimisation | Lithium, FerriteCore | Yes | Optional | | Client-only: shaders, rendering | Sodium, Iris | No | Optional | [Sodium](https://modrinth.com/mod/sodium) is marked client-only; [Lithium](https://modrinth.com/mod/lithium) works on the client or the server alone. The catalogue on our **Plugins** tab does not filter by side, so check that label on Modrinth before you install a rendering mod on the server. What happens on a mismatch differs by loader: - **Fabric:** a mod can declare its `environment` as `client` or `server` in its `fabric.mod.json`, and the [spec](https://wiki.fabricmc.net/documentation:fabric_mod_json_spec) says that decides where "the mod should be considered for loading". A well-made client-only mod is skipped on a server. - **Forge:** the [sides page](https://docs.minecraftforge.net/en/latest/concepts/sides/) explains that by default a mod "will cause a red X if the versions on client and server differ" in the server list. A red X means a player is missing a mod or has a different version. A modpack keeps everyone in line: players import the same pack in a launcher such as Prism Launcher, and the server runs it through the **Modpack** template. ## 4. Crashes Work through crashes in this order. 1. **Read the console.** The **Console** tab streams the server log. Fabric stops with a list of unmet requirements when a dependency is missing: its spec says a failed `depends` "causes a hard failure". NeoForge does the same for a missing `required` dependency, says its [mod files page](https://docs.neoforged.net/docs/gettingstarted/modfiles/). 2. **Open the crash report.** The [Fabric crash guide](https://docs.fabricmc.net/players/troubleshooting/crash-reports) says crash reports go in the `crash-reports` folder; on our servers it sits next to `mods` in **Files**. Look at the first mod in the stack trace, but the guide warns that many mods named there "could mean there are some compatibility issues between the mods". 3. **Check versions.** "A mod that worked on version 1.21.8 for instance, might not work anymore on 1.21.11", warns the Fabric docs. A mod for the wrong loader or version is the most common cause. 4. **Remove client-only mods.** The NeoForge guide admits that telling them apart "often requires trial and error"; shaders and rendering mods are the usual suspects. 5. **Halve the list.** If nothing points at a mod, move half the jars out of `mods`, restart, and repeat on the half that crashes. 6. **Memory.** If the console shows **Low memory**, the heap ran out. Add RAM in **Server → Performance** or drop heavy mods; our RAM guide explains the numbers. If the server starts but players cannot join, a red X or a disconnect at login is usually a client mismatch from step 3. Our [can't connect guide](https://1up-servers.com/en/blog/cant-connect-to-minecraft-server/) covers the rest. ## 5. Update or switch loader To move to a new Minecraft version, stop the server and use the **Version change assistant** on the **Worlds** tab. It takes a backup first, lists the catalogue mods that have no build for the new version, and lets you go back in one click for a few days. Jars you uploaded by hand are not in that list: check them yourself. After the change, press **Update all** on the **Plugins** tab. Switching loader is a new server. The template is fixed when you create a server, so a Fabric server cannot become a Forge server from the panel. Create a second server with the other template (Pro holds two), download the world from the first one and bring it in with **Import a world** on **Files**. Fabric mods do not carry over: install the Forge builds of the same mods, if they exist. **Minecraft: Java Edition 24/7 from Starter** Your own Minecraft: Java Edition server online around the clock on the Starter plan, €5.00 a month. [Start a modded Minecraft server on Starter](https://1up-servers.com/en/signup/?plan=starter&game=mc-java) Tested on Minecraft: Java Edition 26.3 (the default version in our wizard) with Fabric Loader 0.19.5 and Forge 66.0.9, the builds published on 2026-10-05. The panel steps come from our code and production catalogue, not from a recorded run. **Change log** - 2026-10-05: first version. - 2026-10-08: panel names updated: the Game and Server tabs replace the old Settings tab. - 2026-10-26: Starter has 4 GB of RAM, so Forge mods now start on Starter; modpacks still need Pro. NOT AN OFFICIAL MINECRAFT SERVICE. NOT APPROVED BY OR ASSOCIATED WITH MOJANG OR MICROSOFT. ## Frequently asked questions Yes, on Java Edition. Run a mod loader such as Fabric or Forge, put the mod jars in the server's mods folder and restart. Every player needs the same loader and mods. About the author[Baurtock](https://1up-servers.com/en/blog/author/baurtock/)Founder, developer and support NOT AN OFFICIAL MINECRAFT SERVICE. NOT APPROVED BY OR ASSOCIATED WITH MOJANG OR MICROSOFT. ## Keep reading [Minecraft: Java Edition · 8 min**Minecraft server.properties Explained: Every Key, Default and Panel Field**](https://1up-servers.com/en/blog/minecraft-server-properties-explained/)[Minecraft: Java Edition · 7 min**Fix Minecraft Server Lag: TPS, spark and Paper Settings**](https://1up-servers.com/en/blog/fix-minecraft-server-lag/)[Minecraft: Java Edition · 10 min**25 Best Minecraft Plugins for a Friends Server (Paper 26.3)**](https://1up-servers.com/en/blog/best-minecraft-plugins-friends-server/)