Best Free Message-Oriented Middleware

RabbitMQ is lightweight and easy to deploy on-premises and in the cloud. It supports multiple messaging protocols. RabbitMQ can be deployed in distributed and federated configurations to meet high-scale, high-availability requirements. With tens of thousands of users, RabbitMQ is one of the most popular open-source message brokers. From T-Mobile to Runtastic, RabbitMQ is used worldwide at small startups and large enterprises. RabbitMQ is lightweight and easy to deploy on-premises and in the cloud. It supports multiple messaging protocols. RabbitMQ can be deployed in distributed and federated configurations to meet high-scale, high-availability requirements. RabbitMQ runs on many operating systems and cloud environments and provides a wide range of developer tools for most popular languages. Deploy with Kubernetes, BOSH, Chef, Docker and Puppet. Develop cross-language messaging with favorite programming languages such as Java, .NET, PHP, Python, JavaScript, Ruby, Go, etc.

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 like HubSpot, NASCAR and Webflow trust us to power their critical applications - reliably, securely and at serious scale. Ably’s products place composable realtime in the hands of developers. Simple APIs and SDKs for every tech stack, enable the creation of a host of live experiences - including chat, collaboration, notifications, broadcast and fan engagement. All powered by our scalable infrastructure.

Solace PubSub+ Platform helps enterprises design, deploy and manage event-driven systems across hybrid and multi-cloud and IoT environments so they can be more event-driven and operate in real-time. The PubSub+ Platform includes the powerful PubSub+ Event Brokers, event management capabilities with PubSub+ Event Portal, as well as monitoring and integration capabilities all available via a single cloud console. PubSub+ allows easy creation of an event mesh, an interconnected network of event brokers, allowing for seamless and dynamic data movement across highly distributed network environments. PubSub+ Event Brokers can be deployed as fully managed cloud services, self-managed software in private cloud or on-premises environments, or as turnkey hardware appliances for unparalleled performance and low TCO. PubSub+ Event Portal is a complimentary toolset for design and governance of event-driven systems including both Solace and Kafka-based event broker environments.

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.

StreamNative redefines streaming infrastructure by seamlessly integrating Kafka, MQ, and other protocols into a single, unified platform, providing unparalleled flexibility and efficiency for modern data processing needs. StreamNative offers a unified solution that adapts to the diverse requirements of streaming and messaging in a microservices-driven environment. By providing a comprehensive and intelligent approach to messaging and streaming, StreamNative empowers organizations to navigate the complexities and scalability of the modern data ecosystem with efficiency and agility. Apache Pulsar’s unique architecture decouples the message serving layer from the message storage layer to deliver a mature cloud-native data-streaming platform. Scalable and elastic to adapt to rapidly changing event traffic and business needs. Scale-up to millions of topics with architecture that decouples computing and storage.

Responsive applications keep users engaged and developers inspired. Rise to meet these ever-increasing expectations with the DataStax Astra Streaming service platform. DataStax Astra Streaming is a cloud-native messaging and event streaming platform powered by Apache Pulsar. Astra Streaming allows you to build streaming applications on top of an elastically scalable, multi-cloud messaging and event streaming platform. Astra Streaming is powered by Apache Pulsar, the next-generation event streaming platform which provides a unified solution for streaming, queuing, pub/sub, and stream processing. Astra Streaming is a natural complement to Astra DB. Using Astra Streaming, existing Astra DB users can easily build real-time data pipelines into and out of their Astra DB instances. With Astra Streaming, avoid vendor lock-in and deploy on any of the major public clouds (AWS, GCP, Azure) compatible with open-source Apache Pulsar.

With Azure SignalR Service, adding real-time communications to your web application is as simple as provisioning a service—no need to be a real-time communications guru! You don't have to provision and maintain servers just because you need real-time features in your solution. SignalR Service is fully managed which makes it easy to add real-time communication functionality to your application. No more worrying about hosting, scalability, or load balancing – it's all handled automatically. Benefit from everything Azure has to offer! Easily integrate with services such as Azure Functions, Azure App Service, Azure Active Directory, Azure Storage, Azure Analytics, Power BI, IoT, Cognitive Services, Machine Learning, and more. Use the SignalR Service Premium Tier to leverage enterprise capabilities such as auto-scaling, higher SLA, Azure Availability Zone support, and rate limiting. Send advanced metrics to Azure Monitor or integrate with other monitoring solutions.