Minecraft:Development resources

Minecraft is written in Java and C++, and although the class files are obfuscated, the community has figured out most of the inner workings of Minecraft. Notch himself gave notes on a common format used by Minecraft, the Minecraft:NBT format. From this, the community has derived information for the files that use the NBT format.

NBT format

The Minecraft:NBT format is used by almost every file in Minecraft. It is a GZipped tree structure of tags, where each tag has a type, name, and payload based on the type. In 1.2 snapshot 12w07a and above, an additional tag type was added to the original tag types that existed since Minecraft:Indev.

Level formats

Each edition of Minecraft uses its own file format to store levels. The following information about the different level file formats can be used by software developers to create map editors, servers, level generators, and other programs. Minecraft:Blocks, Minecraft:items, Minecraft:data values, and Minecraft:entities are common to all map types.

Java Edition

• Minecraft:Java Edition Classic level format used by Classic.
• Minecraft:Java Edition Indev level format used by Indev.
• Minecraft:Java Edition Alpha level format used by Alpha (previously Infdev).
• Minecraft:Java Edition level format used by 1.0
  • Minecraft:Anvil file format used by 1.0 (from 1.2)
    • Minecraft:Region file format used since Beta (from Beta 1.3).
      • Minecraft:Chunk format for the individual 16×256×16 chunks contained in regions.
  • Minecraft:Map item format used to store the colors on the craftable Minecraft:map items.
  • Minecraft:player.dat format used to store the state of players.
  • Structure file format used to store structures saved by the Minecraft:structure block.
  • Minecraft:villages.dat format used to store the state of villages in a level.

Bedrock Edition

• Minecraft:Bedrock Edition level format used by Bedrock Edition.

Other formats

• Minecraft:Servers.dat format used to store the list of saved multiplayer servers.
• Schematic files are NBT files used by a few 3rd party utilities to store sections of a map for later use.

Libraries

These are community-created libraries to interact with the various files used by Minecraft.

Name/link	Language	Description
MCModify	Java/C++	Library that allows for loading, manipulating, and saving all Minecraft formats.
nbt	Java	Flexible and intuitive library for reading and writing Minecraft's NBT format on the JVM, with emphasis on custom tags.
Example NBT Class	Java	Basic brute-force Java class that reads and writes NBT structures.
Example Classic Level Class	Java	Java class(es) to read and write Classic levels.
Substrate	C#	C# classes to load and edit levels.
Craft.Net	C#	C# library for writing server software and messing with worlds and such.
c10t	C++	An open source cartography tool.
libnbt++	C++	C++ library to read and write NBT structures.
CNBT	C	C library to read and write NBT structures.
Minecraft-Perl	Perl	Perl library to edit Minecraft files.
Python NBT Parser	Python	Python library to edit NBT structures.
pymclevel	Python	Python library to edit Minecraft levels. MCEdit was built upon this library.
J2Blocks	Java	A Java library for easy generation of Minecraft worlds.
nbtlib	Python	A modern python library to read and edit nbt data.

Server protocol

Minecraft:Classic server protocol used by the Minecraft Classic Creative Multiplayer server.

For info on the current multiplayer protocol, see the wiki.vg merge project on this wiki.

Resources

URL	Program	OS	Notes
https://www.delorie.com/djgpp/	Djgpp, GCC for Windows	Windows
https://www.cygwin.com/	Cygwin the Linux-on-Windows (Unix Environment)	Windows	Good for Windows users.
https://code.visualstudio.com/	Microsoft Visual Studio Code	Windows	Free version of Visual Studio, an IDE and compiler for C++, C# and Visual Basic.
https://www.oracle.com/java/technologies/downloads/	Java Development Kit download	Cross-platform	Essential if you want to interpret Java code