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What is MC World Compressor?

MC World Compressor is a free, open-source web application designed to compress Minecraft Java Edition worlds efficiently. Built with Next.js and React, it provides a modern, user-friendly interface for optimizing your Minecraft worlds without compromising the integrity of your builds and explored areas. The application can reduce world file sizes by 47-75% on average, making it easier to share, backup, and store your Minecraft worlds.

Free & Open Source

Licensed under CC BY-NC-SA 4.0, completely free to use for non-commercial purposes.

Multi-Language Support

Available in English, Spanish, Hindi, and Arabic with automatic locale detection.

Large File Support

Upload worlds up to 4GB with intelligent chunked file transfer.

Smart Optimization

Uses the thanos library for intelligent chunk analysis and removal.

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How It Works

MC World Compressor uses the thanos library, a powerful tool for Minecraft world optimization. The compression process is intelligent and preserves everything that matters while removing unused data.
1

Analyze Chunks

The system scans your Minecraft world and analyzes all chunks to identify which ones contain player modifications, structures, or important data.
2

Remove Unused Chunks

Chunks that have never been explored or modified by players are safely removed. This includes:
  • Unvisited terrain chunks
  • Empty or untouched areas
  • Redundant world data
Your builds, items, and progress are completely safe - only truly unused chunks are removed.
3

Recompress & Download

The optimized world is recompressed and made available for download. The result is a smaller file that loads faster and takes up less storage space.

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Compression Process

Here’s a visual breakdown of how the compression works:
The compression is non-destructive to your actual gameplay data. All explored areas, builds, player inventories, and world progress remain intact.

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Key Features

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Supported Formats

MC World Compressor accepts multiple archive formats:
  • .zip - Standard ZIP archives
  • .tar - TAR archives
  • .tar.gz - Gzip-compressed TAR archives

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Upload Size Limits

Maximum upload size is 4GB. If your world is larger, consider removing unnecessary files (logs, backups) before compressing.

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Multi-Language Interface

The application automatically detects your browser language and supports:
  • English (EN)
  • Spanish (ES)
  • Hindi (HI)
  • Arabic (AR)
You can manually switch languages using the language selector in the navigation.

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Real-World Results

Based on actual compression results:

Small Worlds

24MB → 6MB75% size reduction

Medium Worlds

94MB → 29MB69% size reduction

Large Worlds

1340MB → 715MB47% size reduction
Worlds with more unexplored areas typically achieve higher compression ratios. Well-explored worlds with extensive builds will see smaller (but still significant) reductions.

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Architecture Overview

The application is split into two parts:

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Frontend (This Repository)

Built with:
  • Next.js 16+ - React framework with App Router
  • React 19 - Latest React features
  • TailwindCSS 4 - Modern, utility-first styling
  • Custom i18n - Multi-language translation system

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Backend

The backend handles:
  • File upload processing with chunked transfer
  • Integration with the thanos library for chunk analysis
  • Compression queue management
  • Download delivery
The frontend requires a backend URL configured via the NEXT_PUBLIC_BACKEND_URL environment variable. See the Quickstart guide for setup instructions.

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Use Cases

Reduce the size of regular world backups to save storage costs and speed up backup/restore operations. Particularly useful for server administrators managing multiple worlds or maintaining historical backups.
Make it easier to share your Minecraft creations by reducing file sizes for upload to cloud storage, forums, or direct downloads. A 1GB world becomes much more manageable at 500MB.
Free up disk space on your server or local machine by removing chunks you’ve never explored. Perfect for long-running worlds that have accumulated unnecessary terrain data.
Smaller world files mean faster loading times when starting your Minecraft server or loading the world in single-player.

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What Gets Preserved

MC World Compressor is designed to be safe and non-destructive. The following data is always preserved:
  • All player builds and structures
  • Player inventories and ender chests
  • World spawn point and game rules
  • Entity data (mobs, animals, items)
  • Explored chunks and terrain
  • All dimensions (Overworld, Nether, End)
  • Village data and generated structures
  • Redstone contraptions and mechanisms

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What Gets Removed

Only unused data is removed:
  • Chunks that have never been visited by players
  • Empty terrain in unexplored regions
  • Redundant region files with no modifications

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License

MC World Compressor is licensed under Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0).

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What This Means:

  • ✅ Free to use for personal and non-commercial purposes
  • ✅ Open source - you can view, modify, and reuse the code
  • ✅ Share freely - distribute and remix as needed
  • ❌ No commercial use - cannot be used for profit
  • ⚖️ Attribution required - must credit this project
  • 🔄 ShareAlike - derivatives must use the same license
Exception: You can accept donations to cover server hosting costs, as long as donations don’t unlock features or differentiate users in any way.

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Next Steps

Quickstart Guide

Get the application running locally in minutes

Development Setup

Set up your development environment

Features

Explore compression features in detail

Deployment

Deploy your own instance