Media, methods, and systems are disclosed for hosting an event-based application. Application instructions corresponding to processing steps to be performed in response to particular events are received from a development environment. The events are associated with a group-based communication channel. An application comprising computer-executable instructions is generated based on the application instructions and metadata associated with the events. In response to detecting one or more of the events, execution of the computer-executable instructions is triggered. A response is received corresponding to output from applying the processing steps to the events. A message is posted into the respective communication channel corresponding to the response.