In the Mule ecosystem, you use a drag-and-drop flow builder of canned components to build flows that typically ingest events, do something to them, and possibly write someplace. Almost anywhere, you can also inject your custom code.
You deploy these flows in their engine, where they're kept alive. You can self-host the engine, but they also offer it in their cloud.
Then you can choose to frontend it with a HTTP API that you build in their builder, and choose to put it in your organization's private store, or the public store for others to use. There's management dashboards too.
There's hundreds of other products or product combinations that could be described in the same sort of vague language, but MuleSoft ships and supports a particular environment and a particular collection of tools that does it pretty well.
Ultimately, the goal of all of these is the reduction of the effort around every other piece besides the parts that are custom to your unique circumstances.
I believe they are in EAI - Enterprise Application Integration space. Broadly speaking this is a "swiss army knife", if you want to take a CSV file from an FTP site and load it into a relational database, then do queries off a table and POST JSON to a webhook, It can do any of those things.
Depends on what part of Mulesoft your talking about.
Traditionally it offered an Enterprise Service Bus solution but has been moving to an interesting collaborative API Management/Development solution over the past couple years. They really sell the idea of using an API network to hook up your integrations and then use Mulesoft's product to manage it.
