Paper 26.3 Minecraft Server Setup Guide

What is Paper?

Paper is free Minecraft Java Edition server software with performance changes and support for Bukkit, Spigot, and Paper plugins. Players join with Java Edition 26.3; they don’t install the server’s plugins.

Checked 18 September 2026: Paper 26.3 is available as an experimental build. The official download page still offers 26.2 by default, and the 26.3 build API labels build 17 ALPHA. Test with a separate world or a copy of your server before upgrading your main world.

This guide covers Windows. My Paper video covers 1.20; use the versions and commands below for 26.3.

Install Java 25

Paper 26.1 and newer require Java 25 . Download the Windows x64 JDK 25 MSI from Eclipse Temurin . During installation, leave the PATH option enabled .

Open a new terminal and run:

1	java -version

It should report version 25. If Windows selects an older installation, run where.exe java to find it.

Download Paper 26.3

Create a folder such as C:\GameServers\Paper26.3.

Select Toggle experimental builds for 26.3, then download a 26.3 build. Once 26.3 becomes the main download, the experimental toggle won’t be needed. Save the JAR in your server folder as paper.jar.

In File Explorer, enable View → Show → File name extensions so you can check filenames.

Create start.bat

Save this beside paper.jar as start.bat, without .txt on the end:

start.bat

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@echo off cd /d "%~dp0" java -Xms4G -Xmx4G -jar paper.jar --nogui pause

This uses Paper’s documented startup command . The Java heap starts at 4 GiB and has a 4 GiB limit. Change both 4G values to adjust it. Leave memory for Windows, Java’s other memory use, and Minecraft if you’re playing on the same PC.

Paper’s script generator recommends trying modern Java without extra garbage-collector flags first. Start with this command before adding Aikar’s flags from an older tutorial. pause keeps startup errors visible.

First launch and whitelist

Run start.bat. The first launch creates eula.txt and stops. Read the Minecraft EULA . If you agree, change eula=false to eula=true in that file, save it, and run start.bat again.

Wait for the server to finish starting. For an invited-player server, enter these commands in its console, without a leading /:

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whitelist on whitelist add YourName whitelist add FriendName whitelist list

Use each player’s Java Edition username. Running whitelist on explicitly avoids relying on defaults or settings carried over from an older server. Paper documents whitelisting and permissions here .

Enter op YourName if you need administrator commands. Keep operator access limited to trusted administrators.

Join and configure the server

Launch Minecraft: Java Edition 26.3, open Multiplayer → Direct Connection, and enter localhost on the hosting PC. Confirm you can join before opening internet access.

To edit settings, enter stop in the console and wait for shutdown. Open server.properties and edit the existing entries:

See Paper’s settings reference for other options. Save and restart with start.bat.

Install plugins

Find plugins on Hangar or the author’s own download page. Check that the release supports 26.3 and install its required dependencies. Support for Bukkit’s API doesn’t guarantee an old plugin works on a new Minecraft version.

1. Stop the server.
2. Put the plugin’s .jar file in the server’s plugins folder.
3. Start the server and run plugins in the console.

A green entry means the plugin is enabled. For red or missing entries, read logs\latest.log for version or dependency errors. Restart after plugin changes. Paper’s plugin installation guide explains these checks.

Fabric and Forge mods don’t run on Paper. Use this server’s plugins folder, not a mods folder.

Firewall and port forwarding

For Java Edition connections, open PowerShell as Administrator and allow inbound TCP 25565:

1	New-NetFirewallRule -DisplayName "Paper Server TCP 25565" -Direction Inbound -LocalPort 25565 -Protocol TCP -Action Allow

Run ipconfig and find your active adapter’s IPv4 address, such as 192.168.1.10. Players on your network connect to that address.

For friends outside your network, reserve that local address in your router, then forward external TCP 25565 → your server PC’s IPv4 address, internal TCP 25565. They connect using your public IPv4 address. Keep using the local address at home.

If you change server-port, change the firewall and forwarding rules too, and append :port to connection addresses. Multiple routers and ISP CGNAT need additional handling; see the 26.3 networking instructions . Test from outside your network while Paper is running.

Backups, updates, and migration

Use stop to save and shut down. After it exits, copy the entire server folder to a separate backup location, including worlds, plugins, plugin data, and configuration. Back up external plugin databases separately if you use them.

For an update, test a copy first: install compatible plugin releases, replace paper.jar with the chosen Paper build while stopped, then start it and check logs\latest.log. Join and verify your inventory, builds, dimensions, and plugins. Paper’s update guide covers the replacement process.

World migration changed in 26.1. Paper’s migration instructions distinguish these cases:

• Vanilla to Paper: after a full backup, Paper converts the world storage when started with the existing world.
• Spigot/CraftBukkit to Paper: current world layouts aren’t directly interchangeable. Follow the documented Spigot/CraftBukkit-to-vanilla conversion first, then migrate vanilla to Paper.
• Paper to vanilla: some world data files need relocating. Follow the current instructions, not the pre-26.1 DIM-1/DIM1 recipe.

Paper can’t load custom blocks or items that require Fabric or Forge mods. Keep the original modded server backup. To reverse an upgrade, restore the complete backup with its matching server and plugins; don’t run older software against the converted world.

Troubleshooting

• Java error: check java -version. If needed, replace java in start.bat with the quoted full path to Java 25’s bin\java.exe.
• Unable to access jarfile: check paper.jar and start.bat are together and filenames match.
• Not whitelisted: run whitelist add YourName in the console.
• Connection timed out: test localhost, then LAN, then an outside connection. Check TCP 25565 at each step.
• Plugin errors: check the first error in logs\latest.log, the plugin’s supported versions, and its dependencies.