Abstract: Integrating applications into a communication system via steps of workflows is described. In an example, the communication system can receive a request to integrate a functionality of an application into the communication system via an application extension. The functionality can be associated with a step to be integrated in a workflow. Responsive to receiving the request, the communication system can cause an input user interface to be presented via the computing device, wherein the input user interface is configured to receive application extension data. Based at least in part on associating the application extension data with a trigger event identifier, the communication system can store an indication of the step in a repository and cause a selectable user interface element associated with the step to be presented via a group-based communication interface. Selection of the selectable user interface element can cause the step to be included in the workflow.