Apache ActiveMQ vs Eclipse Amlen

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 Amlen is a self-hosted MQTT server for IoT and web messaging. It supports MQTT versions 3 through 5 over TCP/IP and WebSockets, plus JMS, and can convert messages between MQTT and JMS. A protocol plug-in SDK lets users add other protocols, including options for legacy sensors that cannot use MQTT. The Amlen Bridge forwards MQTT messages to another MQTT server or IBM Event Streams for IBM Cloud, with filtering, topic mapping, multiple forwarders, and REST API configuration and monitoring. Security controls include TLS profiles, user ID and password authentication against a configured LDAP server, and policy-based authorization for connections, topics, subscriptions, and queues. Administrators can manage message hubs and endpoints through a WebUI or REST Administration APIs. Supported client platforms include C, Java, Android, iOS, and JavaScript. Server and WebUI downloads are listed for RHEL and AlmaLinux 8, 9, and 10. The free software has configurable delivery guarantees. One limitation is that Amlen supports a single LDAP server connection, so users and groups must be provided through that server.