Eclipse Mosquitto vs Faye

Eclipse Mosquitto is a free, open-source message broker for MQTT 5.0, 3.1.1 and 3.1. It uses publish/subscribe messaging, a pattern suited to connected devices such as sensors, phones, embedded computers and microcontrollers. The project describes it as lightweight, with applications from low-power single-board computers to full servers. Mosquitto runs on Linux, macOS, Windows and self-hosted environments. The project also provides a C library for MQTT clients and the mosquitto_pub and mosquitto_sub command-line tools. MQTT and MQTT over WebSockets are supported, and delivery guarantees are configurable. A public test server offers plain MQTT, TLS, client-certificate TLS and WebSocket options. The project lists manufacturing, healthcare, automotive and smart-home systems among broker application areas. Community support is best effort through GitHub, a mailing list, Matrix and Cedalo forums. Cedalo offers hosted or on-premises instances, consulting and custom development.

Faye is a publish-subscribe messaging system that uses the Bayeux protocol. It provides message servers for Node.js and Ruby, plus clients for servers and major web browsers. Browser clients rely on a Faye server to relay messages; they can retry after a lost connection and redeliver dropped messages. Transport adapters cover WebSocket, HTTP long-polling, Cross Origin Resource Sharing, and JSON-P callback-polling. Server and client extensions can intercept or modify messages, including to add subscription authentication. The monitoring API reports handshakes, subscriptions, unsubscriptions, publishes, and disconnections. Faye runs on Linux, macOS, and Windows, and can be self-hosted. Its default in-process engine cannot span multiple front-end web servers, but Redis and Couchbase engines are documented for distributed deployments. Faye is free and open source under the Apache 2.0 license; the listed plan is free. Install the Node.js server through npm or the Ruby server through RubyGems.