Fabric 26.3 FREE Minecraft Server Setup Guide

What you’ll need

Fabric loads mods into Minecraft: Java Edition. This guide sets up a Fabric 26.3 server on Windows. The software is free; the hosting PC must stay on while people play.

Fabric supports 26.3 , with Loader 0.19.5 recommended at release. Support was checked on 18 September 2026. Individual mods need their own 26.3-compatible releases, so check your mod list before upgrading an existing world.

Install Java 25

Mojang’s 26.3 metadata specifies Java 25. Install the Windows x64 JDK 25 MSI from Eclipse Temurin , keeping its PATH option enabled.

Open a new terminal and run:

1	java -version

Check that the version begins with 25. If Windows still selects an older installation, where.exe java shows which executable it finds. The Java bundled with the Minecraft Launcher doesn’t necessarily make java available to your server’s batch file.

Download the Fabric server

Create an empty folder such as C:\GameServers\Fabric26.3. Open the official download page:

Select Minecraft 26.3, the latest stable Loader, and the latest Installer. At the time of writing, those are 0.19.5 and 1.1.2, as listed by the Loader and Installer APIs.

Download the executable server JAR into your folder and name it fabric-server.jar. This launcher downloads Minecraft and installs Fabric when first run , so the first start needs internet access.

This replaces the separate Install → Download server jar → Generate steps used in the older installer guide . Use the executable server launcher download for the batch file below.

Create start.bat

Enable View → Show → File name extensions in File Explorer. Save this as start.bat beside fabric-server.jar; check that it isn’t named start.bat.txt.

start.bat

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@echo off cd /d "%~dp0" java -Xms1G -Xmx4G -jar fabric-server.jar nogui pause

-Xms1G starts the Java heap at 1 GiB; -Xmx4G caps it at 4 GiB. These are example settings, not a RAM requirement for every modpack. Follow your pack’s requirements and leave memory for Windows, Java’s other allocations, and your Minecraft client.

First launch and EULA

Run start.bat. After downloading its files, the server stops with an EULA message. Read the Minecraft EULA . If you agree, change eula=false to eula=true in eula.txt, save it, and run start.bat again.

For an existing modpack, follow its server installation instructions before generating its world. For a new custom setup, start with no mods to check that Fabric launches, then enter stop in the console before adding them.

Add mods and Fabric API

Put your server’s mod JARs in its mods folder, creating that folder if needed. Keep the JARs intact. Check each download for Minecraft 26.3, Fabric, and its listed dependencies. Forge and NeoForge builds of a mod won’t load through Fabric. Fabric’s mod installation guide explains the version and loader checks.

Install Fabric API in mods when a mod requires it. Choose an API release supporting 26.3. Fabric Loader and Fabric API are separate downloads.

Check each mod’s documentation for its requirements. Fabric’s server installation notes warn that some client-only mods crash dedicated servers. A vanilla client can join only when the installed server mods permit it.

Restart after adding mods. For a custom selection, add a few at a time so a startup failure has a short list of suspects.

Whitelist and joining

Minecraft 26.3 enables the whitelist by default . In the server console, enter commands without /:

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whitelist on whitelist add YourName whitelist add FriendName whitelist list

Replace the example names with Java Edition usernames. Use op YourName if you need administrator commands.

Players who need client mods should install Fabric for 26.3, add the required mods and dependencies to that client’s mods folder, then select the Fabric profile in their launcher.

On the hosting PC, open Multiplayer → Direct Connection and enter localhost. Test this before opening access to other computers.

Let friends connect

Stop the server before editing server.properties. Keep online-mode=true, white-list=true, server-port=25565, and server-ip= empty. Restart afterward.

Open PowerShell as Administrator and allow incoming player connections:

1	New-NetFirewallRule -DisplayName "Minecraft Fabric TCP 25565" -Direction Inbound -LocalPort 25565 -Protocol TCP -Action Allow

Run ipconfig and find your active adapter’s IPv4 address. Friends on the same network connect to that address, for example 192.168.1.10.

For internet access, forward TCP 25565 on your router to the server PC’s local IPv4 address. Friends outside your network use your public IPv4 address. Mods with extra network services, such as voice chat, can require additional ports documented by their authors.

The vanilla guide’s networking section covers router settings, multiple routers, and CGNAT. Keep the server running when testing from outside your network.

Backups and updates

Enter stop and wait for the server to exit. Copy the entire server folder to a separate backup location, including the world, mods, configs, whitelist, and launcher.

Test upgrades in another copy. Download a new executable launcher for the intended Minecraft and Loader versions, use the filename in start.bat, and install compatible versions of every mod and dependency. Check that players can join and that their inventories, builds, and modded content survive before using the updated copy for your group.

Keep the old backup with its original software. Removing a content mod can remove its blocks and items; downgrading the launcher won’t restore them.

Troubleshooting

• Java not found or UnsupportedClassVersionError: check java -version. Replace java in the batch file with the quoted full path to Java 25’s bin\java.exe if needed.
• Unable to access jarfile: check the downloaded filename and keep the JAR beside start.bat.
• Incompatible mod set: read Fabric’s listed missing dependencies and version requirements. Check Minecraft, Loader, Fabric API, and each named mod.
• Crash after adding a mod: inspect logs\latest.log and any file in crash-reports. Recheck whether the mod supports dedicated servers.
• Can’t join: check the whitelist and client mod versions first. For timeouts, test localhost, then LAN, then internet access.

Keep the full error log when asking for help. Fabric’s log guide explains the difference between logs and crash reports.