Apache ActiveMQ vs Eclipse Mosquitto

Apache ActiveMQ is an open-source messaging and Integration Patterns server for applications that exchange messages. It is self-hosted and supports OpenWire, STOMP, AMQP 1.0, MQTT 3.1, and REST. Listed client languages include Java, C, C++, C#, Ruby, Perl, Python, and PHP. Messaging features include message groups, virtual and composite destinations, wildcards, and enterprise integration patterns. ActiveMQ fully supports JMS 1.1 and J2EE 1.4+ messaging, including transient, persistent, transactional, and XA modes; support for Jakarta Messaging 3.1 and JMS 2.0 is partial. Transport options include in-VM, TCP, SSL, NIO, UDP, multicast, JGroups, and JXTA, with JDBC persistence and a high-performance journal. Browser access is available through a REST API and Ajax web streaming. Security options include pluggable providers, JAAS authentication, XML-configured authorization, and user, group, and destination permissions. ActiveMQ Classic costs nothing under the Apache License 2.0.

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.