LCM Documentation

LCM is a set of libraries and tools for message passing and data marshalling, targeted at real-time systems where high-bandwidth and low latency are critical. It provides a publish/subscribe message passing model and automatic marshalling/unmarshalling code generation with bindings for applications in a variety of programming languages.


  • Low-latency inter-process communication

  • Efficient broadcast mechanism using UDP Multicast

  • Type-safe message marshalling

  • User-friendly logging and playback

  • No centralized “database” or “hub” – peers communicate directly

  • No daemons

  • Few dependencies

Supported platforms / languages

  • Platforms:

    • GNU/Linux

    • OS X

    • Windows

    • Any POSIX-1.2001 system (e.g., Cygwin, Solaris, BSD, etc.)

  • Languages

    • C

    • C++

    • C#

    • Java

    • Lua

    • MATLAB

    • Python (3.6 and later)


These are community-maintained forks of LCM that add extra functionality. While they’re not part of the official LCM distribution, they’re linked to here in case people find them useful.

API Reference

Additional resources

Publications and application notes

  • LCM Overview - Describes the design principles of LCM, the best place to start for a quick understanding of LCM. 6 pages (PDF). - IROS, Taipei, Taiwan, Oct 2010.

  • Technical Report - An expanded version of the overview, provides a more comprehensive description. 17 pages (PDF).
    • Technical Report MIT-CSAIL-TR-2009-041, Massachusetts Institute of Technology, 2009

  • UDP Multicast Setup

  • Java application notes

Who uses LCM?

LCM was originally developed in 2006 for the MIT DARPA Urban Challenge team, and has since been used in many robotic and autonomous systems, in both research and production environments. Its users have included:

  • Autonomos GmbH

  • BAE Systems

  • Bender Robotics

  • Carnegie Mellon University

  • ETH Zurich

  • Ford Motor Company

  • Georgia Tech

  • Google

  • Korea Advanced Institute of Science and Technology (KAIST)

  • MIT

  • Soar Technology

  • University of Michigan

  • Volvo Car Group

  • Woods Hole Oceanographic Institute

If you’re using LCM for development or production, we’d love to hear about it. Let us know by sending a message to the mailing list.

Indices and tables