Best Free Message-Oriented Middleware of 2025

Sashulin Message Broker(SMB) is a programmable software message broker that allows applications, systems and services to exchange information and communicate. By using messaging and transformations, "conversations between services" written in different languages and platforms are realized. SMB provides developers with standard business components. The business process flow can be realized by connecting the components. This allows developers to focus on the core logic.

RabbitMQ is a lightweight solution that can be effortlessly deployed both on-premises and in cloud environments. It is compatible with various messaging protocols, making it versatile for different use cases. Furthermore, RabbitMQ can be configured in distributed and federated setups, which cater to demanding scalability and high availability needs. With a vast user base, it stands out as one of the leading open-source message brokers available today. Organizations ranging from T-Mobile to Runtastic leverage RabbitMQ, showcasing its adaptability for both startups and large enterprises. Additionally, RabbitMQ is compatible with numerous operating systems and cloud platforms, offering a comprehensive suite of development tools for popular programming languages. Users can deploy RabbitMQ using tools like Kubernetes, BOSH, Chef, Docker, and Puppet, facilitating seamless integration into their existing workflows. Developers can also create cross-language messaging solutions using their preferred programming languages, such as Java, .NET, PHP, Python, JavaScript, Ruby, and Go, enhancing its utility across various projects.

Ably is the definitive realtime experience platform. We power more WebSocket connections than any other pub/sub platform, serving over a billion devices monthly. Businesses trust us with their critical applications like chat, notifications and broadcast - reliably, securely and at serious scale.

Solace is a specialist in Event-Driven-Architecture (EDA), with two decades of experience providing enterprises with highly reliable, robust and scalable data movement technology based on the publish & subscribe (pub/sub) pattern. Solace technology enables the real-time data flow behind many of the conveniences you take for granted every day such as immediate loyalty rewards from your credit card, the weather data delivered to your mobile phone, real-time airplane movements on the ground and in the air, and timely inventory updates to some of your favourite department stores and grocery chains, not to mention that Solace technology also powers many of the world's leading stock exchanges and betting houses. Aside from rock solid technology, stellar customer support is one of the biggest reasons customers select Solace, and stick with them.

HiveMQ is the most trusted enterprise MQTT platform, purpose-built to connect anything via MQTT, communicate reliably, and control IoT data. The platform can be deployed anywhere, on-premise or in the cloud, giving developers the flexibility and freedom they need to evolve as their IoT deployment grows. HiveMQ is reliable under real-world stress, scales without limits, and provides enterprise-grade security to meet the needs of organizations at any stage of digital transformation. The extensible platform provides seamless connectivity to the leading data streaming, databases, and data analytics platforms, plus offers a custom SDK for a perfect fit in any stack.

Integrating real-time communications into your web application using Azure SignalR Service is incredibly straightforward—just set up the service without needing extensive expertise in real-time communications! There's no necessity to manage or provision servers simply for the sake of adding real-time capabilities to your project. The fully managed nature of the SignalR Service allows for an effortless inclusion of real-time communication features, freeing you from concerns about hosting, scalability, or load balancing since those are managed automatically. Take advantage of the comprehensive offerings from Azure! You can seamlessly connect with a variety of services like Azure Functions, Azure App Service, Azure Active Directory, Azure Storage, Azure Analytics, Power BI, IoT, Cognitive Services, and Machine Learning, among others. By opting for the Premium Tier of SignalR Service, you can tap into advanced enterprise features including auto-scaling, a higher Service Level Agreement (SLA), support for Azure Availability Zones, and rate limiting. Additionally, you can send detailed metrics to Azure Monitor or pair with other monitoring solutions to keep track of your application's performance effectively. Enjoy the simplicity of adding powerful real-time communication capabilities to your applications while leveraging the full potential of Azure’s robust ecosystem.

StreamNative transforms the landscape of streaming infrastructure by combining Kafka, MQ, and various other protocols into one cohesive platform, which offers unmatched flexibility and efficiency tailored for contemporary data processing requirements. This integrated solution caters to the varied demands of streaming and messaging within microservices architectures. By delivering a holistic and intelligent approach to both messaging and streaming, StreamNative equips organizations with the tools to effectively manage the challenges and scalability of today’s complex data environment. Furthermore, Apache Pulsar’s distinctive architecture separates the message serving component from the message storage segment, creating a robust cloud-native data-streaming platform. This architecture is designed to be both scalable and elastic, allowing for quick adjustments to fluctuating event traffic and evolving business needs, and it can scale up to accommodate millions of topics, ensuring that computation and storage remain decoupled for optimal performance. Ultimately, this innovative design positions StreamNative as a leader in addressing the multifaceted requirements of modern data streaming.

Engaging applications captivate users while motivating developers to innovate. To meet the growing demands of the digital landscape, consider utilizing the DataStax Astra Streaming service platform. This cloud-native platform for messaging and event streaming is built on the robust foundation of Apache Pulsar. With Astra Streaming, developers can create streaming applications that leverage a multi-cloud, elastically scalable architecture. Powered by the advanced capabilities of Apache Pulsar, this platform offers a comprehensive solution that encompasses streaming, queuing, pub/sub, and stream processing. Astra Streaming serves as an ideal partner for Astra DB, enabling current users to construct real-time data pipelines seamlessly connected to their Astra DB instances. Additionally, the platform's flexibility allows for deployment across major public cloud providers, including AWS, GCP, and Azure, thereby preventing vendor lock-in. Ultimately, Astra Streaming empowers developers to harness the full potential of their data in real-time environments.

Eclipse Mosquitto is a message broker that is open source and licensed under EPL/EDL, designed to support various versions of the MQTT protocol, including 5.0, 3.1.1, and 3.1. This broker is notably lightweight, making it ideal for deployment on a wide range of devices, from low-power single-board computers to robust server systems. The MQTT protocol itself offers an efficient way to handle messaging through a publish/subscribe architecture, which is particularly well-suited for applications in the Internet of Things, enabling communication with low-power sensors or mobile devices like smartphones, embedded systems, and microcontrollers. In addition to the broker, the Mosquitto project also includes a C library that facilitates the creation of MQTT clients, alongside the widely used command line clients, mosquitto_pub and mosquitto_sub, which enhance user interaction with the MQTT protocol. Overall, Mosquitto serves as a versatile tool for developers aiming to implement messaging solutions in a variety of applications.

Middleware Observability & management software for Messaging, event processing, and Streaming Across Hybrid Clouds (MESH). - 360 degree situational awareness® with complete observability of Integration MESH - Manage configuration, administration and deployment in a secure manner and automate them. - Track and trace transactions, messages, and flows - Collect data, monitor performance, and benchmark it meshIQ provides granular controls for managing configurations in the MESH, reducing downtime and allowing quick recovery after outages. It allows you to search, browse, track and trace messages in order to detect bottlenecks, speed up root cause analysis, and detect bottlenecks. Unlocks integration blackbox for visibility across MESH infrastructure in order to visualize, analyse, report and predict. Delivers the capability to trigger automated action based on predefined criteria or intelligent AI/ML actions.

CoreDX DDS is a user-friendly, multi-platform, and multi-language library designed for Inter-Process Communication (IPC). It boasts impressive performance with minimal overhead and low latency, making it ideal for real-time control and facilitating high message throughput for substantial data transfer. This library ensures secure, resilient, adaptable, and dynamic data exchange. Built on open standards to guarantee interoperability and sustainability, CoreDX DDS is the go-to IPC solution for a diverse range of distributed software applications, including mobile gaming, consumer electronics, medical devices, advanced Department of Defense systems, and space-operating robots. Developers appreciate CoreDX DDS for its straightforward usability and the rich set of features it offers, many of which are challenging to achieve manually and are absent in other IPC libraries. With capabilities such as built-in end-to-end security, data filtering and storage, data presentation, and event notification options, CoreDX DDS empowers developers to concentrate on their application development without getting bogged down by complex communication tasks. Ultimately, this makes CoreDX DDS not only a practical choice but also a valuable resource for enhancing productivity in software development.