mooR is a network-accessible, multi-user, programmable system for building online social environments, games, and collaborative spaces. Think of it as a virtual world where participants can not only interact with each other, but also program and modify the environment itself.

mooR is a modern, from-scratch rewrite of LambdaMOO, maintaining full compatibility with existing LambdaMOO 1.8.x databases while adding significant enhancements.

📖 For comprehensive documentation, see our mooR Book.

📦 Repository Migration Notice (August 2025): We've recently moved our primary repository from GitHub to Codeberg. If you're viewing this on GitHub, please consider switching to Codeberg for the latest updates, issue tracking, and contributions.

MOOs offer a unique digital experience through:

• Collaborative storytelling where participants build a shared narrative
• Live programming - modify the world while you're in it
• Community-driven development through persistent interactions and relationships
• Rich interaction that engages users through both traditional command-line and modern web interfaces
• Complete customizability - everything from objects to commands can be programmed

mooR builds on the foundation of MUDs (Multi-User Dungeons) and similar multiplayer online environments that have fostered creative communities for decades. Like modern sandbox games, MMORPGs, and social platforms, MOOs provide persistent worlds where players can build, create, and collaborate. What sets MOOs apart is their emphasis on live programming and community-driven content creation - imagine if Minecraft's creative mode, Discord's community features, and a code editor all lived in the same space.

In a world of throwaway apps and walled gardens, mooR is cheerfully dragging the future into the past - taking the best ideas from decades of online community building and rebuilding them with modern technology.

mooR is approaching its 1.0 release and is currently in late alpha, with a focus on documentation, testing and performance tuning. It successfully runs databases imported from LambdaMOO, with real world workloads, and lives through our cruel stress and performance testing regimen.

Database formats and APIs may still change before the stable release, and we reserve the right to keep adding features right up until the last minute.

Repository: The primary mooR repository is hosted on Codeberg with a mirror on GitHub.

Runtime improvements:

• Fully multithreaded architecture for modern multicore systems
• Web frontend client
• Directory-based import/export format for version control integration
• Modular architecture for easier extension

Language enhancements:

• UTF-8 strings, 64-bit integers, binary values
• Proper boolean values (true/false)
• Maps: associative containers (["key" -> "value"])
• Lexically scoped variables with begin/end blocks
• List/range comprehensions ({x * 2 for x in [1..5]})
• Lambda functions: anonymous functions with closures ({x, y} => x + y)
• Symbol literals ('mysymbol) like Lisp/Scheme (optional)
• UUID object identifiers (optional)
• Anonymous objects with automatic garbage collection (optional)
• Lightweight immutable objects ("flyweights") (optional)

Modern infrastructure:

• Fast, durable, transactional database
• Support for multiple client protocols (web, telnet)
• Easy deployment via Docker

The easiest way to get started is with Docker Compose:

docker compose up

For faster builds during development, the default configuration uses debug builds. For production deployment with optimized performance, use:

BUILD_PROFILE=release docker compose up

Note: Debug builds compile significantly faster (especially on resource-constrained systems like Docker Desktop on macOS) while still providing good performance for development and testing.

This starts four services:

• moor-daemon: The backend MOO service
• moor-telnet-host: Traditional telnet interface on port 8888
• moor-web-host: REST API and WebSocket server for web clients
• moor-frontend: Web client served via nginx on port 8080

Connect via:

• Web: http://localhost:8080
• Telnet: telnet localhost 8888

The server comes pre-loaded with an extraction of LambdaCore, providing a ready-to-explore virtual world.

For more detailed setup instructions, see the Docker Compose Setup section in the mooR Book.

For frontend development and testing, you can run just the daemon and web client without Docker:

npm run full:dev

This starts the moor-daemon and web development server, accessible at http://localhost:3000. This setup excludes telnet and provides hot-reloading for frontend development, but it requires installing some dependencies. See the web client's readme for details.

mooR offers several opportunities for contribution:

Core Development (Rust):

• Server architecture improvements
• New builtin functions
• Performance optimizations
• Protocol extensions

World Building (MOO language):

• Creating new cores and experiences
• Porting existing MOO content
• Building modern web-enabled interfaces

Documentation & Testing:

• Expanding the mooR Book
• Creating tutorials and examples
• Stress testing and bug reports

• Issues: Check our Codeberg Issues for current needs
• Discussion: Join our Discord community
• Development: See the mooR Book for architecture details
• Support: Consider sponsoring the project to help with ongoing development

Found a bug or have a feature request? Please file an issue on our Codeberg issue tracker.

When reporting bugs, please include:

• Steps to reproduce the issue
• Expected vs actual behavior
• Your system information (OS, Docker version if applicable)
• Relevant log output or error messages

• 📖 Complete Documentation - The comprehensive mooR Book
• 🏗️ Server Architecture - Technical overview
• 💻 MOO Programming Language - Language reference
• 🚀 Running a Server - Deployment guide

mooR is licensed under the GNU General Public License v3.0. See LICENSE for details.

This ensures the software remains open and free, in keeping with the the original LambdaMOO project.