MCA JSON

Web · Windows · Mac · Linux

Freedom report

Three barsScore 6.6

Free tierA free tier is on its own pricing page
Runs widely4 of 6 device platforms
DocumentedPlans, terms and facts published

MCA JSON is ranked #2 of 35 in Minecraft world editors on Freedom251. It runs on Linux, macOS, Web, Windows. There is a free plan.

MCA JSON plans and pricing

All plans

MCA JSON Free Open-source command-line tools and JavaScript library for MCA/Anvil and NBT files github.com · 9 Oct 2026

Compared on Minecraft world editors

Free plan: Yes
Minecraft editions: java
Region editing: Yes
Supported world formats: MCA (Anvil), NBT, SNBT

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The record

Purpose: MCA JSON provides command-line tools and a JavaScript library for converting Minecraft Anvil and NBT files to JSON, converting back, and modifying data.
Tools: Its command-line tools convert MCA and NBT to JSON, list chunks, find signs, remove chunks, and read player locations.
Library: The TypeScript library provides typed classes and methods for parsing and modifying MCA files, NBT files, and SNBT strings.
Installation: The maker documents global or project installation with npm and says Deno, Bun, pnpm, and other package managers can also be used.
Browser support: The library has no Node-specific tooling requirement and can be bundled for browser environments; it is published as ES modules only.
Minecraft edition: Only Minecraft Java Edition is supported; Bedrock Edition uses a different format.
Version coverage: The maker says region structure and NBT reading work across versions and reports trying files from Minecraft 1.2.1 through 1.21.
Compression: The library reads chunks compressed with zlib, gzip, LZ4, or no compression, while modified chunks are saved with zlib.
Read limitation: Chunks larger than 1 MiB stored in separate .mcc files and chunks using custom compression cannot be read, though they can still be listed and removed.
JSON size: The maker notes that an example mostly untouched region produced about 1 gigabyte of JSON and documents compact and condensed output options.
Runtime: The library works with Node.js 20 and newer.
Support: For problems with other Minecraft versions, the maker asks users to supply a test MCA file and problem description or submit a pull request.
Price from: Free

Where it ranks on Freedom251

Best Minecraft World Editors in 2026#2 of 35

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Sources

github.com/fidian/mca-json· checked 9 Oct 2026