Rebus is a lean service bus implementation for .NET, similar in nature to NServiceBus and MassTransit, only leaner.

These are the goals - Rebus should have:

• a simple and intuitive configuration story
• a few well-selected options
• no doodleware
• dependency only on .NET 4 BCL
• integration with external dependencies via small and dedicated projects
• the best error messages
• a frictionless getting-up-and-running-experience

and in doing this, Rebus should align very well with NServiceBus, allowing users (myself included) to easily migrate to NServiceBus at some point in a project's lifetime, if Rebus for some reason falls short (which I don't think it will).

Oh, and Rebus is free as in beer and speech.

I used to be a happy NServiceBus user, and I'm still using NServiceBus on some projects. It just puzzles me that

• NServiceBus is 60 KLOC spread across 200+ projects - the code is hard to read
• Errors are often hard to diagnose
• Messing up during configuration yields weird errors at best, and no warnings or signs of things being wrong at worst
• NServiceBus went from being absolutely free to be licensed

I realize that NServiceBus is pretty cheap when you think of all the good things it can do for you, but to many people I think the license fee is an annoyance that will hinder them in introducing NServiceBus in all of their awesome projects - Which is a shame!

Then why don't I just use MassTransit then? Well, I wanted to do that, but I had so much trouble figuring out the philosophy of the MassTransit project that I gave up learning how to use it. I don't like how it needs a central runtime service to manage subscriptions, and I had a hard time figuring out how to make it work. And then there's the option of using PGM over MSMQ, but it just didn't work how I wanted it to work. Long story short: Too hard to get started!

Therefore, I wanted to try building a simple alternative to NServiceBus. Mainly as a personal research project, but also for myself to use in projects so I don't have to worry about licensing.

If you want to read more, check out the official Rebus documentation wiki or check out my blog.

One day, maybe I'll tweet something as well... @mookid8000

Rebus is a simple .NET library, and everything revolves around the RebusBus class. One way to get Rebus up and running, is to manually go

var bus = new RebusBus(...);
bus.Start();

// use the bus for the duration of the application lifetime

// remember to dispose the bus when your application exits
bus.Dispose();

where ... is a bunch of dependencies that vary depending on how you want to send/receive messages etc. Another way is to use the configuration API, in which case you would go

var someContainerAdapter = new AdapterForMyFavoriteIocContainer(myFavoriteIocContainer);

Configure.With(someContainerAdapter)
	.Logging(l => l.Log4Net())
	.Transport(t => t.UseMsmqAndGetInputQueueNameFromAppConfig())
	.DetermineEndpoints(d => d.FromRebusConfigurationSection())
	.CreateBus()
	.Start();

// have IBus injected in application services for the duration of the application lifetime

// let the container dispose the bus when your application exits
myFavoriteIocContainer.Dispose();

which will stuff the resulting IBus in the container as a singleton and use the container to look up message handlers. Check out the Configuration section on the official Rebus documentation wiki for more information on how to do this.

Rebus is licensed under Apache License, Version 2.0. Basically, this license grants you the right to use Rebus in any way you see fit.