MCA JSON vs Minecraft Region Fixer

MCA JSON is a command-line toolkit and TypeScript library for handling Minecraft Java Edition region and data files. Its commands convert MCA and NBT data to JSON and back, list chunks, find signs, remove chunks, and inspect player locations. The library supplies typed methods for parsing and changing MCA, NBT, and SNBT data. The maker reports region structure and NBT reading across versions, with files tried from Minecraft 1.2.1 through 1.21. It reads zlib, gzip, LZ4, and uncompressed chunks; changes are saved with zlib. Installation is documented through npm, with Deno, Bun, pnpm, and other package managers also usable. The library can be bundled for browser use, is distributed only as ES modules, and requires Node.js 20 or newer. It supports Java Edition, not Bedrock. Separate .mcc chunks over 1 MiB and chunks using custom compression cannot be read, though they can be listed and removed. A largely untouched region produced about 1 gigabyte of JSON in an example; compact and condensed output options are documented. The software is free.

Minecraft Region Fixer is a free tool for locating problems in Minecraft worlds and region files, with options to replace or remove corrupted chunks. When an older world backup is available, it can use that copy to replace damaged chunks; without one, it can remove them so Minecraft regenerates them. It also scans level.dat and player .dat files and prints warnings, but does not repair those files. Other documented uses include replacing chunks or regions from backups, removing entities, and investigating world problems. The command-line program runs with Python 3.x, not Python 2.x, and includes options for parallel scanning and saving detailed results to a log file. Its usage guide also describes deletion of broken chunks, broken region files, and excess entities. It supports Minecraft region files (*.mca) and world folders on Windows, Linux, and macOS. The project warns that bugs may exist and recommends backing up a world before use; the tool is used at the user's own risk. It is licensed under GPL-3.0.