MassTransit is

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...

.NET-based

Enterprise Service Bus An enterprise service bus (ESB) implements a communication system between mutually interacting software applications in a service-oriented architecture (SOA). It represents a software architecture for distributed computing, and is a special varia ...

(ESB) software that helps .NET developers route messages over

RabbitMQ RabbitMQ is an open-source message-broker software (sometimes called message-oriented middleware) that originally implemented the Advanced Message Queuing Protocol (AMQP) and has since been extended with a plug-in architecture to support Str ...

, Azure Service Bus, SQS, and

ActiveMQ Apache ActiveMQ is an Open-source software, open source message broker written in Java together with a full Java Message Service (JMS) client. It provides "Enterprise Features" which in this case means fostering the communication from more than on ...

service busses. It supports multicast, versioning, encryption, sagas, retries, transactions, distributed systems and other features. It uses a "Control Bus" design to coordinate and the

Rete algorithm The Rete algorithm ( , , rarely , ) is a pattern matching algorithm for implementing rule-based systems. The algorithm was developed to efficiently apply many rules or patterns to many objects, or facts, in a knowledge base. It is used to deter ...

to route. Since it does not include "business monitoring" or a "

business rules engine A business rules engine is a software system that executes one or more business rules in a runtime production environment. The rules might come from legal regulation ("An employee can be fired for any reason or no reason but not for an illegal rea ...

" (and requires programming to implement sagas for orchestration), MassTransit is typically considered to be in the category of "lightweight ESB" software. The project is led by Microsoft MVP and national conference speaker Chris Patterson ("phatboyg"), who is also the author of the TopShelf project, and is co-authored by Dru Sellers. By February 2021 downloads of the package through

NuGet NuGet (pronounced "New Get")And The Winner Is, NuGet
haacke ...

passed 26,000 per week. MassTransit is similar to a commercial offering called NServiceBus, and developers often pick one or the other for their implementation. The similarity is no accident, as the authors note that MassTransit was first built in 2007 as an alternative to NServiceBus, and the projects share the use of some code. Other similar "NuGet" ESB packages include Rebus and Rhino Service Bus.

References

{{.NET .NET software Message-oriented middleware