FluffOS

FluffOS is a high-performance LPMUD driver (game engine) for persistent multiplayer worlds. It is the actively maintained MudOS successor: an LPC compiler and VM, a network server (Telnet, WebSocket, TLS), and hundreds of built-in functions (efuns) your mudlib calls.

Looking up MudOS, LPMUD, or LPC? Start with MudOS, LPMUD, and LPC.

It is not a complete game. A mudlib — a tree of LPC files — is the game. Pick one (Dead Souls, Lima, 泥潭, 侠客行, or anything in fluffos/mudlibs), then point the driver at it.

Get a mud running

Humans: Pick a mudlib and boot it.

Language models: https://www.fluffos.info/llm — the assistant must ask which lib before cloning. (site map: llms.txt · mudlib file: AGENTS.md template).

The current release is branch master (CMake, Ubuntu / macOS / Windows MSYS2 / WebAssembly). See releases.

The three layers

Layer	What it is
LPC	Object-oriented, C-like language. Every room, item, and player is an object.
Driver (FluffOS)	Compiles LPC, runs it, owns connections, databases, and efuns.
Mudlib	Your game: login, commands, rooms, combat, policy. Swap the mudlib, keep the binary.

Full org map — mudlibs, VS Code, converters: the FluffOS ecosystem (fluffos/fluffos, fluffos/dead-souls, fluffos/nt7, fluffos/fluffos-vscode, …).

MudOS is the unmaintained ancestor. LPMUD is the driver + mudlib split. LPC is the language. Glossary: MudOS, LPMUD, and LPC.

Explore

MudOS · LPMUD · LPC

What those words mean, and why FluffOS is the MudOS successor.

Glossary

Start a mud

Pick a mudlib, build the driver, and boot that lib until you get a prompt.

Onboarding

LLM contract

Ask which mudlib, then build, boot that lib, and write its AGENTS.md.

LLM contract

Ecosystem

Every public fluffos/* repo: mudlibs, VS Code, GBK conversion, more.

Org map

LPC language

Types, foreach, operators, async/await, preprocessor, diagnostics.

Language

Efuns

Built-in functions the driver exposes to LPC, grouped by topic.

Efun reference

Applies

Callbacks the driver invokes: master security, object lifecycle, connections.

Apply reference

Concepts

Objects, simul_efuns, hot reload, networking, async and promises.

Guides

Standard library

Pure-LPC helpers shipped with the testsuite: TUI, database, strings.

Stdlib

WebAssembly

Run a full mudlib in the browser, with an LPC ↔ JavaScript bridge.

WASM build

Features

• CMake builds on Ubuntu, macOS, and Windows (MSYS2/MinGW64), plus a WebAssembly target.
• Native UTF-8 (including emoji) and transparent I/O transcoding.
• Telnet, WebSocket, and TLS on the same driver; built-in web client in src/www.
• SHA-512 crypt by default; SQLite, MySQL, and PostgreSQL; async file and DB I/O.
• Native promises and async / await in LPC.
• Hot reload: recompile_object() updates a live program and its clones.
• 64-bit LPC int (always) and float as C double.
• MudOS-compatible mudlibs still run; upgrade from v2017 rather than staying there.

Build and contribute

• Dev environment — editor plugin, LPC highlighter, formatter
• Build from Source · Build for WebAssembly · Troubleshooting
• Driver internals · Command-line tools
• Source: github.com/fluffos/fluffos
• License