mooR is a platform for building multi-user virtual environments that are programmable from the inside. It allows you to write code, create new objects, and modify the world's behaviour in real-time while you are connected to it.
Public shakeout environment for the 1.0 release-candidate track
Live Programming
Most software is built, compiled, and then shipped as a static package. In mooR, the environment is live. Users with the right permissions can "look under the hood" of any object, see its code, and change it immediately.
Whether you're building a new room, an interactive game system, or a collaborative work tool, you build it *within* the system itself, often while interacting with other users who are using the same tools you are currently modifying.
Technical Foundation
Under the hood, mooR is a from-scratch implementation of the LambdaMOO server architecture. LambdaMOO was a pioneering system from the early 90s that proved this model of live, user-programmable environments could scale to thousands of users.
We've rebuilt this engine in Rust to take advantage of modern concurrency, high-performance data structures, and native web integration, creating a stable foundation for the next generation of collaborative software experiments.
Key Features & Enhancements
Runtime Improvements
- Fully multithreaded architecture for modern multicore systems
- Structured web API with OpenAPI 3.1 specification and versioned `/v1` routes
- Official Meadow web client with a separate published `web-sdk` package
- Directory-based import/export format for version control integration
- Modular architecture for easier extension
- Fast, durable, transactional database
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/endblocks - List/range comprehensions (
{x * 2 for x in [1..5]}) - Lambda functions: anonymous functions with closures (
{x, y} => x + y) - UUID object identifiers (optional)
- Anonymous objects with automatic garbage collection (optional)
Project Status
mooR is now on its 1.0 release-candidate track. The
v1.0-release branch has been cut, the codebase is
functionally frozen apart from release-critical fixes, and
1.0.0-rc.1 is planned once the branch has had time
to shake out in real-world use on Timbran Hotel. The project is
open source and available on Codeberg.
Since January, work has focused heavily on performance and release hardening: scheduler overhead reductions, write-path batching and coalescing in the database layer, lower-lock commit internals, better caching along execution flow, and a cleaned-up web surface with a formal API specification and separate client packages. mooR itself is now released under the GNU Affero General Public License v3.0.
If you find value in mooR and would like to support its ongoing development, please consider sponsoring the project.