Reliable Replacer

Each rule names a block to replace and the block that takes its place. Rules apply while new chunks generate, and they can also be run on chunks that already exist, which is called retrogeneration. Every rule can switch retrogeneration off, and a separate toggle decides whether players placing the block trigger the replacement. Filters limit a rule to specific biomes, dimensions, placed features or structures, so a swap can stay inside one area of the world.

The configuration lives in a file named swapper.json in the config folder under reliable replacer, and rules inside it inherit the default settings for retrogeneration and player placement unless a rule overrides them. Changes take effect after a reload, so server owners can test a rule without restarting. Modpack creators can ban items or restrict their use with standard JSON files, and no scripting is needed. A legacy format matches the configuration of Block Swap, so an existing file can be migrated by copying it into the new config.

The mod runs on servers alone, and vanilla clients connect without installing anything. Fabric API is required on Fabric. Cloth Config API and YetAnotherConfigLib (YACL) are optional dependencies. The license is the MIT License, and the source code is open source.