There are many messaging tools that we can use to send messages between systems. We will explore the most popular ones here.
RabbitMQ is open source message broker software (sometimes called message-oriented middleware) that implements the Advanced Message Queuing Protocol (AMQP). The RabbitMQ server is written in the Erlang programming language. Client libraries to interface with the broker are available for all major programming languages.
MassTransit is a lightweight Service Bus for .NET, often used as an abstraction over RabbitMQ when you are using RabbitMQ with .NET.