NSQ: Open-source realtime distributed messaging, billions of messages / day

Aeron and NSQ have slightly different design principles. Which can easily be identified in their feature list. Aeron’s origins are exchanges for fintechs and focus on predictable low latency with a tight standard deviation. NSQ puts heavy emphasis on being a distributed broker less message queue. Performance alone probably isn’t a good basis to measure their utility.

Kafka and Azure EventHub and RedPanda are EventStream system use Retention policy. They can handle very high throughput efficiently but are not transactional and cannot be safely used when data consistency is the priority.

While system like ActiveMQ, Azure service bus, RabbitMQ are transactional message broker each subscriber to a topic has its own mailbox and message are removed from the mailbox when the client acknowledge that the message has been successfully processed. And deleted from the broker when no mailbox still contain the message. They can be used for workflow involving financial transaction (money) and are very safe. But they sometime dont maintain ordering, client might receive message in different order than the publisher put them inside the topic.