There are two main types of workflow integrations that are part of Kinetic's workflow engine: Sources and Handlers. They handle different parts of the integration process for the workflow engine.
Sources are the integration component that takes the input from webhooks (really any API connection) and processes that into an easy to use dataset. This is what gives you menu access to data points from the source system when working in the workflow builder. For example, for the Kinetic Data Platform, using the source changes the predefined options menu from this:
Workflow developers often don't even realize they are interacting with a source. They select it when they create the workflow's tree, but that is all.
Handlers are the snippets of code that perform all the actions in the workflows. These perform all of the CRUD (Create-Retrieve-Update-Delete) actions to any and all other systems as well as constructing loops, echoing values, and transforming data. These make up, with the connectors that connect them, the body of all of the workflows.
Workflow developers work with handlers extensively. Very experienced workflow developers often learn to create their own handlers, as they find they may want to tweak the actions taken in existing handlers.
All sources and handlers are open source. If the source or handler doesn't exist for the system you wish to talk to (and that system has an API), your developers can take the existing code and make the necessary changes to talk to your additional system(s).