#minecraft-server #minecraft #block #entities #chunks #world #logic


Minecraft beta 1.7.3 base data structures and logic for running a world

2 unstable releases

0.2.0 Jan 15, 2024
0.1.0 Jan 2, 2024

#153 in Games

Used in mc173-server


14K SLoC

Minecraft Beta 1.7.3

A work-in-progress Minecraft beta 1.7.3 server made in Rust. This project split the server crate from data structure and logic crate, the latter is made to be used be developers.

  1. Logic crate
  2. Server crate
  3. Contributing
  4. Roadmap

Logic crate

Crates.io Total Downloads

The logic crate mc173 provides the core data structures such as worlds, chunks and entities, but also the behaviors for blocks, items and entities. It also provides a lot of utilities related to Minecraft.

Server crate

Crates.io Total Downloads

The server crate mc173-server is an implementation of the Notchian server protocol, it is built on top of the logic crate and has threaded networking, it also defines protocol structures.


If you're willing to contribute or fork this code, this sections presents the different tools that can be used to understand the Notchian implementation of Minecraft beta 1.7.3 and how to implement it into Rust.

The most important tool is RetroMCP, which is a modern remake of MCP (one of the most important software in Minecraft's modding history). It can be used to automatically decompile and deobfuscate the original archive of Minecraft beta 1.7.3. It can also be used to recompile and reobfuscate the game and then run it, which can be useful to add debugging code, but fortunately it's rare to get to that point. You can read the project's README, it is really well designed and its CLI is intuitive, you just have to choose the b1.7.3 version for both client and server.

Choosing both client and server is really important as these two have slightly different source codes. For example, you have to choose the client or server source code depending on which side of the network protocol you want to understand.

The next step is just to explore the source code, and try to understand how it works! This can be quite challenging sometimes due to the object oriented nature of it, so you should also use a IDE or text editor that support the Java langage and a few important features such as goto definition and class hierarchy (VSCode, IDEA, Eclipse...).

Use the following roadmap either to understand how the completed components have been adapted from Java to Rust, or if you want to contribute and add a feature. The Rust code is also documented as most as possible, so please read the doc comments to really understand how to contribute to the documented code. If you think that the roadmap is incomplete, you can add items as needed.

A tool that can also be useful is a Minecraft CLI launcher that I (Théo Rozier) made, it's called PortableMC and it has really good support for b1.7.3 and the game starts really fast compared to the Mojang launcher. It also fixes in-game skin and some other legacy-related issues.


There is a lot of work to be done in order to provide a fully functional server on parity with the Notchian server, in order to properly achieve this work, the following roadmap summarize implemented and missing components and in which order we should work on them. The priority of each feature is defined by its order in the list.

  • World and chunk data structures
  • World serialization
    • Chunk data
    • Block entity data
    • Entity data
    • Level data
  • Blocks
    • Definitions
    • Item drop
    • Tick scheduling
    • Placing
    • Breaking
    • Redstone (partial)
    • Clicking (partial)
  • Items
    • Definitions
    • Inventory data structure
    • Crafting
      • Definitions
      • Tracker
    • Use/place behaviors
    • Break behaviors
  • Entities
    • Entity data structures
    • Entity behaviors (80%)
  • Server
    • Protocol
    • Network threading
    • Block breaking
      • Long block breaking
      • Instant block breaking
      • Block breaking duration check
    • Players inventory is stored server-side
    • Players can be linked to any entity type
    • Worlds serialization
      • Non-persistent player entities
      • Player entities saved appart
    • Player window
      • Left and right click support
      • Player inventory crafting grid
      • Crafting table
      • Chest
      • Furnace
      • Dispenser
      • Shift-click on items
    • Entity tracking
      • Client-side spawn
  • Lighting engine
  • World generation


~137K SLoC