Open-source Event Streaming Platforms:

Apache Kafka:

Highly scalable and reliable platform for high-volume data streams, widely used for building real-time applications.

Apache Pulsar:

Distributed streaming platform with strong messaging capabilities and support for multiple protocols.

Apache Flink:

Stream processing engine for analyzing and reacting to data streams in real-time.

Apache RocketMQ:

High-performance, open-source messaging platform with low latency and strong persistence.

Apache Samza:

Stream processing framework for building real-time applications with low latency and fault tolerance.

Open-source Event Bus/Message Queues:

RabbitMQ:

Lightweight and general-purpose message queue system, suitable for simple tasks and microservices communication.

ActiveMQ:

Highly scalable and flexible message queue system, supporting various protocols and integrations.

NATS:

High-performance messaging platform with low latency and strong security features, ideal for real-time communication.

Redis Streams:

Stream data structure within the Redis data store, suitable for real-time processing of data feeds.

Commercial Event Streaming Platforms:

Amazon Kinesis:

Scalable and managed event streaming service from Amazon Web Services (AWS).

Azure Event Hubs:

Cloud-based event streaming service from Microsoft Azure.

Google Cloud Pub/Sub:

High-throughput and reliable event streaming service from Google Cloud Platform (GCP).

Solace PubSub+:

Comprehensive platform for event streaming and management with hybrid and multi-cloud support.

Confluent Platform:

Enterprise-grade streaming platform based on Apache Kafka, offering additional features and support.

Event-Driven Frameworks and Libraries:

Spring Cloud Stream:

Framework for building microservices-based applications with message-driven communication.

Akka Streams:

Reactive streams library for building scalable and resilient event-driven applications.

RxJava:

Reactive programming library for asynchronous and event-driven programming.

Eventuate:

Framework for building event-sourced applications with high availability and scalability.