
Datapack Debugger
A fabric mod for Minecraft 1.21, which allows you to set breakpoints in datapacks
About this Mod
Datapack Breakpoint
Introduce
This is a fabric mod for Minecraft 1.21, which allows you to set breakpoints in the game and "freeze" the game when
the breakpoint is reached.
Usage
- Set a breakpoint
In datapack, you can insert #breakpoint into .mcfunction file to set a breakpoint. For example:
#test:test
say 1
say 2
#breakpoint
say 3
say 4
In this case, after the game executes say 2, the game will be "frozen" because it meets the breakpoint.
When the game is "frozen", you can still move around, do whatever you want, just like execute the command tick freeze.
So you can check the game state, or do some debugging.
- Step
When the game is "frozen", you can use the command /breakpoint step to execute the next command. In above example,
after the game meets the breakpoint, you can use /breakpoint step to execute say 3, and then use /breakpoint step
to execute say 4. When all commands are executed, the game will be unfrozen and continue running.
- Continue
When the game is "frozen", you can use the command /breakpoint move to unfreeze the game and continue running.
- Get Macro Arguments
By using /breakpoint get <key>, you can get the value of the macro argument if the game is executing a macro function.
For example:
#test:test_macro
say start
#breakpoint
$say $(msg)
say end
After executing function test:test_macro {"msg":"test"}, we passed the value test to the macro argument msg and
then the game will pause before $say $(msg). At this time, you can use /breakpoint get msg to get the value test.
Available Versions
How to Install Datapack Debugger on Your Server
Order Server
Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).
Set fabric Loader
In the panel under "Egg", select the fabric loader and matching Minecraft version (1.21).
Install Mod
Open the mod browser in the dashboard and search for "Datapack Debugger". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
1.21
Server-side
✓ RequiredRecommended RAM
4 GB(min. 3 GB)Frequently Asked Questions
Datapack Debugger server crashes on startup – what to do?
Most common cause: wrong fabric version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.21). You can switch loaders with one click in the panel.
Is Datapack Debugger compatible with fabric?
Datapack Debugger officially supports fabric for Minecraft 1.21. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with Datapack Debugger – how to optimize performance?
Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Datapack Debugger consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.
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