# lcm-proj/lcm

Lightweight Communications and Marshalling

Repository: https://github.com/lcm-proj/lcm
Canonical: https://ross.abutalabs.com/products/lcm
Language: Java
License: LGPL-2.1
License Family: copyleft
Last push: 2026-08-30T14:39:17+00:00

## Health v2 (maintenance only)
Score: 72/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 100, release rhythm 21, longevity 100
- inputs: {"age_days": 4373, "days_push": 3, "days_rel": 314, "gap_med": 304, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1203, forks 430 (observed 2026-09-01T02:14:03.659241+00:00)

## What it is
LCM (Lightweight Communications and Marshalling) is a set of libraries and tools for low-latency, high-bandwidth publish/subscribe message passing with type-safe marshalling code generation. It targets real-time systems such as robotics, supports multiple languages (C, C++, Java, Python, Lua, MATLAB), and requires no central broker or daemons.

## Use cases
- pass sensor data between processes in a robotics stack with low latency
- generate type-safe message serialization code for multiple languages
- broadcast messages over UDP multicast without a central broker
- log and replay message streams for debugging
- build real-time inter-process communication for embedded or simulation systems

## When to choose
- you need low-latency pub/sub messaging for real-time or robotics systems
- you want automatic marshalling codegen across C, C++, Java, Python, and Lua
- you want a dependency-light, daemon-free messaging layer
- you need efficient UDP multicast broadcast on a LAN

## When to avoid
- you need messaging over the internet or across unreliable WANs
- you require brokered features like queues, persistence, or guaranteed delivery
- you need Go or C#/.NET bindings, which are unmaintained
- you want a modern ecosystem with rich tooling like Kafka or DDS

## Facets
- artifact type: library
- maturity: stable
- function: serialization, message-queue, middleware, networking
- domain: robotics, microservices, embedded-systems
- platform: windows, python, jvm, cpp, c, lua
- tags: pub-sub, udp-multicast, marshalling, code-generation, real-time-systems, inter-process-communication, real-time, linux, macos

## Member repositories
- lcm-proj/lcm (main) score 72

## Provenance
- Observed fields: from GitHub, fetched 2026-09-01T02:14:03.659241+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:20:36.471699+00:00, confidence not recorded.
  - readme: https://github.com/lcm-proj/lcm (fetched 2026-09-01T02:14:03.659241+00:00, sha 522b535ea96b)
- Data as of 2026-08-30T08:39:29.467469+00:00.