Expressat

Expressat is a cross-platform messaging and event-processing framework designed to provide high-throughput, low-latency communication for distributed applications. It supports publish-subscribe and request-reply messaging models, with a pluggable transport layer and broker-based topology. The design emphasizes predictable latency, resiliency, and operational simplicity, with a focus on real-time analytics and streaming pipelines.

Originating as an open-source project in the mid-2010s, Expressat evolved through community contributions and corporate sponsorship. The project released its first stable version in 2015 and has since implemented multi-broker clustering, backpressure handling, durable storage, and enhanced security features. Governance is community-led with occasional enterprise advisory roles.

Its architecture centers on a broker that routes messages, a collection of language-specific client libraries, and an administration API. The system uses a compact binary wire protocol, supports topic-based routing, durable queues, and message replay. Delivery semantics include at-least-once and, with careful configuration, exactly-once delivery. Security options include Transport Layer Security (TLS), pluggable authentication (SASL), and per-topic access controls. Expressat can be deployed on-premises or in the cloud and is designed to run in containerized environments or bare-metal installations.

Deployments commonly involve edge gateways feeding central processing clusters, real-time dashboards, and microservice orchestration. The framework is valued for low end-to-end latency, straightforward operational tooling, and clear up-time behavior under load. Performance is highly influenced by topology, networking, and the chosen durability guarantees.

Related systems include Apache Kafka, RabbitMQ, NATS, and MQTT brokers, with Expressat often chosen for its combination of low latency and flexible routing.