Eclipse Amlen

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, as well as JMS, and can convert messages between MQTT and JMS. A protocol plug-in SDK lets users add custom protocols, including 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-based configuration and monitoring. Security controls include TLS profiles, user ID and password authentication against a configured LDAP server, and policies for connections, topics, subscriptions, and queues. Administrators 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. Amlen is free and has configurable delivery guarantees. It supports only one LDAP server connection, so users and groups must be supplied through that server.

Amlen offers protocol flexibility, bridging, and policy controls in a self-hosted server. The single-LDAP-server limit and supported download environments are key details for prospective users.

Amlen may suit teams building IoT or web messaging systems that need MQTT, JMS, or custom protocol support. It is for organizations able to operate self-hosted software and use a single LDAP server connection.

Overview

Eclipse Amlen is an open-source messaging server for IoT and web applications, designed for teams that operate their own infrastructure. It is most compelling when a deployment needs MQTT alongside JMS or custom protocol support. Teams that depend on users and groups from multiple LDAP servers should look elsewhere.

Key features

Amlen handles MQTT versions 3 through 5 over TCP/IP and WebSockets, and also supports JMS, including conversion between MQTT and JMS messages. That gives teams a way to connect device messaging with JMS-based applications without splitting those workloads across separate servers. MQTT clients are supported for C, Java, Android, iOS, and JavaScript.

A protocol plug-in SDK extends the server to protocols beyond its native support, including those used by legacy sensors that cannot use MQTT. The Bridge can forward MQTT traffic to another MQTT server or IBM Event Streams for IBM Cloud. Filtering, topic mapping, multiple forwarders, and REST-based configuration and monitoring make it useful for controlled routing between systems; a simple MQTT-only deployment may not need that integration layer.

Security options include TLS profiles, user ID and password authentication against a configured LDAP server, and policies for connections, topics, subscriptions, and queues. The policy controls let administrators govern both who connects and what messaging actions clients can take. The constraint is one LDAP server connection: organizations that need separate directories for their users and groups cannot connect them independently. Administrators manage message hubs and endpoints through the WebUI or REST Administration APIs.

Pricing

Eclipse Amlen: free. Amlen has a free plan and no free trial; there is no paid plan listed. Because it is self-hosted, the free price makes it a practical option for teams prepared to run the server themselves, rather than a hosted service with a paid tier to scale into.

Platforms

Amlen supports Android, iOS, Linux, web, API, and self-hosted use. Its current stable release offers server and WebUI downloads for RHEL and AlmaLinux 8, 9, and 10, so those are the confirmed environments for teams evaluating a download. The product is described as mature and used by large enterprises in production. Users seeking support can discuss Amlen through Eclipse IoT Matrix channels.

Who it's for

Amlen suits organizations building IoT or web messaging systems that need MQTT/JMS interoperability, custom protocol extensions, or controlled forwarding to other MQTT infrastructure or IBM Event Streams for IBM Cloud. Its self-hosted model and policy controls fit teams that want to administer messaging infrastructure directly. It is a poor fit for organizations that must authenticate against more than one LDAP server, or for teams that need a deployment environment beyond the supported RHEL and AlmaLinux downloads.

Pros and cons

• Pro: MQTT and JMS support with message conversion can bridge device messaging and JMS applications.
• Pro: The protocol plug-in SDK and configurable Bridge provide options for legacy sensors and routed integrations.
• Pro: TLS, LDAP-backed authentication, and policies cover connection and messaging permissions.
• Con: Only one LDAP server can be connected, limiting organizations with identities spread across multiple directories.
• Con: Self-hosting means teams need to operate the server; confirmed stable downloads target RHEL and AlmaLinux versions 8 through 10.

Alternatives

For a broader comparison, browse Message Broker Software.

Lightstreamer is worth considering if a freemium option with a free trial and a demo license capped at 20 concurrent client connections better matches an evaluation or smaller deployment.

SocketCluster is another free, self-hosted choice; it is MIT licensed and has no paid plans listed on its maker’s site.

Moquette is a free alternative for teams comparing self-hosted MQTT software.

ApsaraMQ for MQTT is a paid option for readers seeking a subscription-billed MQTT service rather than Amlen’s free self-hosted model.

Amazon SNS may suit readers looking for a freemium API or web messaging option with a free tier that includes monthly request and notification allowances.

CloudAMQP offers a freemium broker with a free trial and a free plan capped at 40 connections, 200 queues, 20,000 queued messages, and 2 million messages per month.

EMQX is an alternative for teams considering a freemium MQTT platform with a free trial and a serverless plan that has a monthly free quota and up to 1,000 connections.

HiveMQ MQTT Broker is an option for teams comparing a freemium broker with a Lab plan capped at 100 connections and 100 messages per second.

Verdict

Choose Eclipse Amlen if your team wants a free, self-hosted server that can bring MQTT, JMS, custom protocols, and policy controls into one messaging stack. Its clearest reason to choose another product is the single-LDAP-server limit; teams with identities across multiple directories need a different fit.