# eclipse-paho/paho.mqtt.c

An Eclipse Paho C client library for MQTT for Windows, Linux and MacOS. API documentation: https://eclipse-paho.github.io/paho.mqtt.c/

Repository: https://github.com/eclipse-paho/paho.mqtt.c
Canonical: https://ross.abutalabs.com/products/pahomqttc
Homepage: https://eclipse.org/paho
Language: C
License: NOASSERTION
License Family: other
Topics: eclipseiot, mqtt, iot, internet-of-things, eclipse-paho
Last push: 2026-07-21T14:09:03+00:00

## Health v2 (maintenance only)
Score: 76/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 93, release rhythm 39, longevity 100
- inputs: {"age_days": 3913, "days_push": 43, "days_rel": 194, "gap_med": 204.5, "n_releases_24m": 3}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2359, forks 1176 (observed 2026-08-28T04:06:40.792343+00:00)

## What it is
The Eclipse Paho C client library for the MQTT protocol, enabling applications to connect to an MQTT broker to publish messages and subscribe to topics. It provides synchronous and asynchronous APIs with optional SSL/TLS support, plus sample command-line publish/subscribe utilities.

## Use cases
- connect a C application to an MQTT broker
- publish and subscribe to MQTT topics from C
- add MQTT 5.0 messaging to an IoT device
- implement MQTT client with SSL/TLS in C
- build asynchronous MQTT messaging in C
- send sensor data over MQTT from embedded Linux

## When to choose
- you need a mature, well-documented C MQTT client supporting MQTT 3.1.1 and 5.0
- you want both synchronous and asynchronous programming models
- you need SSL/TLS-secured MQTT connections on Windows, Linux, or macOS

## When to avoid
- you need a client in a higher-level language like Python or Java (use the Paho bindings for those)
- you need MQTT-SN or a broker rather than a client library

## Facets
- artifact type: library
- maturity: stable
- function: http-client, networking, sdk, cli
- domain: iot, developer-tools, embedded-systems
- platform: windows, c, cpp, cross-platform
- tags: mqtt, mqtt-client, pub-sub, mqtt5, ssl-tls, eclipse-paho, iot-messaging, messaging, linux, macos

## Member repositories
- eclipse-paho/paho.mqtt.c (main) score 76

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:40.792343+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 2026-08-30T02:36:13.437143+00:00, confidence not recorded.
  - readme: https://github.com/eclipse-paho/paho.mqtt.c (fetched 2026-08-28T04:06:40.792343+00:00, sha fa321a775aa0)
  - homepage: https://eclipse.org/paho (fetched 2026-08-29T10:16:54.006319+00:00, sha 5a44edd4cbb2)
  - site_page: https://eclipse.dev/paho/documentation (fetched 2026-08-29T10:16:54.015715+00:00, sha f5e1055ce593)
- Data as of 2026-08-30T08:39:29.467469+00:00.