
Reliable Replacer
A lightweight utility for replacing one block with another, both during worldgen and afterward.
Screenshots


About this Mod
Reliable Replacer
A lightweight utility for replacing one block with another, both during worldgen and afterward.
This mod allows modpack creators to effortlessly ban items or restrict their
usage using standard JSON files, without the need for complex scripts.
What About Block Swap?
I'm glad you asked! I made Reliable Replacer because of some of my personal frustrations with Block Swap. Here are
some reasons to consider switching!
Why Reliable Replacer?
- Reliable Replacer is frequently updated and supports the latest versions, while as of the time of writing this, Block
Swap is stuck on 1.20.1. - Live config reloading! Run
/reloadand see your changes instantly take place. - Reliable Replacer is fully server-side, so it's compatible with Vanilla clients!
- Advanced filtering:
- Filter swaps by biome, dimensions, placed feature, coordinates, or structure!
- Toggle retrogen on or off per rule.
- Toggle player placement replacing per rule.
- Much more flexible configuration, supporting simple JSON configuration in user-defined folders and integrating with
Cloth Config. - Per-rule toggleable persistence:
- Decide if replacement blocks should inherit the properties of the old block.
- Doesn't require any external libraries.
Migrating From Block Swap
Making the switch is easy! Reliable Replacer supports a legacy format designed to work exactly like Block
Swap's configuration.
When you first launch the game with Reliable Replacer installed, a swapper.json file will be automatically generated
in your config/reliable_replacer folder. This file uses a simple key-value pair format identical to Block Swap.
To migrate, simply copy the "swapper" block from your old configuration into this file:
{
"swapper": {
"oreganized:lead_door": "supplementaries:netherite_door",
"farmersdelight:rope": "supplementaries:rope",
"minecraft:dirt": "minecraft:stone",
...
}
}
Note: Rules defined in swapper.json automatically inherit default settings (retrogen enabled, replace on player
placement, etc.). For more advanced control, use the standard rule format.
Features
A full feature list is available on
the Modded Minecraft Wiki.
For information and examples on how to use the mod, please also refer to
the wiki.
Quick-Start Example
Create a file called my_replacement.json, or whatever else you'd like, in config\reliable_replacer:
[
{
"inputs": [
"minecraft:dirt"
],
"output": "minecraft:diamond_block",
"biomes": [
"minecraft:plains"
],
"min_y": "-30",
"max_y": "64",
"player_blocks": "true",
"keep_nbt": "true"
},
{
"inputs": [
"minecraft:stone"
],
"output": "minecraft:gold_ore"
}
]
License
Available Versions
How to Install Reliable Replacer on Your Server
Order Server
Order a Minecraft Java server with at least 4 GB RAM (6 GB recommended).
Set fabric Loader
In the panel under "Egg", select the fabric loader and matching Minecraft version (26.1.2).
Install Mod
Open the mod browser in the dashboard and search for "Reliable Replacer". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
26.1.2, 1.21.1, 1.20.1
Server-side
✓ RequiredRecommended RAM
6 GB(min. 4 GB)Frequently Asked Questions
Reliable Replacer 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 4 GB RAM is allocated and the loader matches the mod version (26.1.2). You can switch loaders with one click in the panel.
Is Reliable Replacer compatible with fabric and forge and neoforge?
Reliable Replacer officially supports fabric, forge, neoforge for Minecraft 26.1.2, 1.21.1, 1.20.1. Note: Forge and Fabric mods are NOT cross-compatible – pick one loader and stick with it. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with Reliable Replacer – how to optimize performance?
Recommended RAM: 6 GB (per 5 players). Use /spark profiler to check if Reliable Replacer 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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Rent Modded Server
Install Reliable Replacer with just one click on your server.