Julti
A Java program by DuncanRuns that automates speedrunning with several Minecraft instances at once: resetting, the wall, window sizes and scripts. Julti works through the Windows API, so it runs on Windows.
Purpose
Lets you run and reset several Minecraft instances from one program, so you reset worlds on a wall instead of one at a time.
Setup Guide
Download Julti-1.6.1.jar from the GitHub releases page. Version 1.6.1 came out on January 1, 2025 and is still the latest.
Set up your instances in MultiMC or Prism Launcher. Julti finds both launchers by itself and reads the instance names from the MultiMC instance config.
Put the mods you play with in every instance. Only mods listed on mc.sr/mods are legal for runs.
Open Julti and launch your instances from it. Then choose how you want to reset, for example on a wall that shows all of them.
Show the wall through an OBS projector, or use the JuWaWi plugin (Julti Wall Window), which needs no OBS at all but, as the changelog admits, is not as good as a projector.
Add scripts from the official scripts browser in the scripts menu, import one from a GitHub gist, or write your own in Lua.
On Minecraft 1.16.1, the changelog tells players to use Jingle instead, the same author's program for a single instance.
Features
- +Resetting several instances at once, with wall and multi reset styles
- +Launching instances, with MultiMC and Prism Launcher detected automatically
- +JuWaWi, a wall window that works without OBS
- +Lua scripts, an official scripts browser and script import from GitHub gists
- +Plugins, with Move Resize included for resizing windows and a magnifier with a ruler for measuring eyes
- +The PaceMan Tracker plugin built in
- +Support for the ColorMC launcher
- +Update checks, with an option to include pre-releases
Julti or Jingle?
Both programs are made by DuncanRuns. Julti is built for several instances at once and Jingle for a single instance, which is where the names come from: Julti for multi, Jingle for single.
Julti's changelog for version 1.6.0 says 1.16.1 players should use Jingle anyway, and on 1.16.1 SeedQueue now runs the wall inside one game. A wall of separate Minecraft windows is still Julti's job.
Jingle picks up an instance when you launch it from the vanilla launcher, MultiMC or a fork such as Prism, or ColorMC. Its main tab clears old worlds while keeping the last 36, makes the game a borderless window and packages the worlds and logs needed for verification, which works best with SpeedRunIGT 14.0 or later. Where MCSR Fairplay supports your version, its own file packaging is the better choice. Jingle 2.0 comes with the Coop Mode and Extra Keys scripts and the OBS Link, PaceMan Tracker, Standard Switcher and Program Launching plugins.
How Julti handles a wall
Since version 0.20 Julti reads WorldPreview's state output to tell what each instance is doing, and the changelog credits that for making it more stable and consistent.
- Dynamic Wall shows a smaller wall, 2x2 by default, and moves locked instances to a lock bar at the bottom of the screen.
- Play Next Lock puts you in the locked instance that has loaded the most.
- Smart Switch sends you to a locked instance that has already loaded when the one you picked hasn't.
- Affinity gives more CPU cores to the instance you are about to play and to instances that just got a reset. A button sets the values back to the recommended defaults.
- Sync Instances copies the mods, config and resource packs of the first instance to all the others.
- Utility Mode, toggled with Ctrl+U in the main window, switches off most multi-instance features and leaves only the reset hotkey and script hotkeys, for practice, ranked or tournament instances.
Reset counters and verification files
Julti keeps its files in a .Julti folder. The total reset count is in resets.txt and the count for the current session in sessionresets.txt. If Julti crashes, the command sessionresets followed by a number puts the session count back, and every profile saves the total every 100 resets so it doesn't fall back by thousands.
Right click an instance in the instances panel and choose Package Files For Submission to collect the files a verifier needs from that instance in one place.
Julti also writes a warning to its log when an instance has a mod that isn't legal, and before launching an instance it sets fullscreen:false in options.txt so the game doesn't start in fullscreen.
Notes
Julti's changelog calls 1.6.0 possibly the last version unless pull requests come in or PaceMan Tracker needs an update, and 1.6.1 only updated that tracker. For 1.16.1 there is now SeedQueue, a mod that runs the wall inside a single instance and is meant to replace multi-instancing. Julti's source is on GitHub under the MIT license.
Questions about Julti
How do I stop Julti from deleting a world?
Start the world name with an underscore, or put a file called Reset Safe.txt in the world folder. Clear Worlds skips both. It only deletes worlds with typical speedrun names such as New World, Random Speedrun #, Set Speedrun # and Practice Seed, and it keeps the six most recently played of those.
Can I use Julti without OBS?
Yes. JuWaWi, the Julti Wall Window plugin that comes with Julti, draws the wall without OBS. It doesn't render at 60 FPS but draws single frames of an instance when it reaches certain states, and locks are plain colored borders, so an OBS projector still looks better.
Does Julti run on macOS or Linux?
No. Julti works through the Windows API, so it only runs on Windows.