RabbitMQ is another option. Clustering is fragile, but it's fine if you just need a single-node: https://www.rabbitmq.com/ https://www.rabbitmq.com/ There are

RabbitMQ is another option. Clustering is fragile, but it's fine if you just need a single-node: https://www.rabbitmq.com/ https://www.rabbitmq.com/ There are also proprietary systems like Solace: https://solace.com/ https://solace.com/ Other than that, there are embedded queuing/log libraries or you can just dump the messages into a key/value store or write them out to a file yourself.