MCA JSON vs MCA Selector

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.

MCA Selector is a free tool for selecting and modifying chunks and regions in Minecraft Java Edition world saves. It can export, delete, or edit selected areas using filters such as data version, last update time, and inhabited time; multiple conditions can be chained. Custom one-line Groovy scripts and a Script Editor extend filtering. The chunk editor exposes the full NBT structure, including points of interest and entity data, allowing tags to be changed, added, deleted, or moved. Users can import chunks from another world with offsets and overwrite options, and copy or paste selections through the system clipboard.

Customizable color-gradient overlays show per-chunk values. A command-line mode handles operations including selection creation, chunk import and export, deletion, region defragmentation, NBT changes, and image generation. Downloads include Windows, macOS, and Linux builds, plus a universal JAR. MCA Selector supports Anvil .mca region files. The project warns that snapshot-generated worlds may not work even when a version appears in its support table, and recommends backing up worlds because the tool can modify or delete chunks.