A Minecraft server, written from scratch in Rust.

Multi-version from the first commit.

The packet codec was written multi-version from commit one, because retrofitting it later is a rewrite rather than a refactor. Protocol work is implemented against decompiled game sources rather than community wiki data, and where the two disagreed, the decompile won.

An embedded runtime, for plugins only.

Bukkit and Paper plugins genuinely are compiled bytecode, so a Java runtime is embedded to load them, plus a launcher that hosting panels expect. The boundary is enforced by a test that runs on every change: with the runtime disabled the server must still boot, and every feature except plugin loading must still work.

There is a line-count ratchet on the Java tree, so the exception cannot quietly grow.

Parity is the exit criterion, not the vibe.

The worldgen phase does not finish when the terrain looks right. It finishes when output is block-identical to a real vanilla server across ten seeds.

Worldgen defects are the expensive class, because they are latent in every chunk already written to disk. Fixing one does not repair the world it already produced, and ordinary unit tests pass straight over them.