Celluloid provides a simple and natural way to build fault-tolerant concurrent programs in Ruby. With Celluloid, you can build systems out of concurrent objects just as easily as you build sequential programs out of regular objects. Recommended for any developer, including novices, Celluloid should help ease your worries about building multithreaded Ruby programs.

Much of the difficulty with building concurrent programs in Ruby arises because the object-oriented mechanisms for structuring code, such as classes and inheritance, are separate from the concurrency mechanisms, such as threads and locks. Celluloid combines these into a single structure, an active object running within a thread, called an "actor", or in Celluloid vernacular, a "cell".

By combining concurrency with object oriented programming, Celluloid frees you up from worry about where to use threads and locks. Celluloid combines them together into a single concurrent object oriented programming model, encapsulating state in concurrent objects and thus avoiding many of the problems associated with multithreaded programming. Celluloid provides many features which make concurrent programming simple, easy, and fun:

Code Quality Rank: L2
Monthly Downloads: 4,528,648
Programming language: Ruby
License: MIT License
Latest version: v0.18.0

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Gem Version MIT licensed Build Status Maintained: no Gitter Chat

Celluloid is a framework for building asynchronous and multithreaded Ruby programs using object-oriented concepts.

Revival Process Underway

Celluloid is in the process of being refactored and released back into the wild during Google Summer of Code. The next era will not have one individual active maintainer, but a team of collaborators. Going forward, previously dormant maintainer Donovan Keme is returning to support future primary maintainer Emese Padányi during GSoC 2020. Her plan extends past the Summer program, and aims to revive the community and codebase of Celluloid together. Backing this process are Harsh Deep and GSoC alumni Dilum Navanjana. We welcome your collaboration and contributions in this massive work.

The codebase is being refactored to pursue a stable release with no deprecation warnings, and with this cleaned up:


Diagram meticulously developed by Emese Padányi

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Please see the Celluloid Wiki for more detailed documentation and usage notes.

The following API documentation is also available:

See also: Projects Using Celluloid

  • Reel: An "evented" web server based on Celluloid::IO
  • DCell: The Celluloid actor protocol distributed over 0MQ
  • ECell: Mesh strategies for Celluloid actors distributed over 0MQ
  • Celluloid::IO: "Evented" IO support for Celluloid actors
  • Celluloid::ZMQ: "Evented" 0MQ support for Celluloid actors
  • Celluloid::DNS: An "evented" DNS server based on Celluloid::IO
  • Celluloid::SMTP: An "evented" SMTP server based on Celluloid::IO
  • nio4r: "New IO for Ruby": high performance IO selectors
  • Timers: A generic Ruby timer library for event-based systems

Contributing to Celluloid

  • Fork this repository on github
  • Make your changes and send us a pull request
  • Pull requests will be reviewed for inclusion in the project


Copyright (c) 2011-2018 Tony Arcieri, Donovan Keme.

Distributed under the MIT License. See LICENSE.txt for further details.

*Note that all licence references and agreements mentioned in the Celluloid README section above are relevant to that project's source code only.