Inngest is a serverless event platform that aggregates events from internal and external systems, allowing users to automatically run serverless code in response to these events as multi-step workflows. It's designed to make building event-driven systems fast and easy by handling timeouts, retries, error handling, and offering visual debugging. Users can coordinate between events, version each workflow, collaborate with non-developers, and run any code in any language as part of a workflow. Inngest is useful for various scenarios such as on signup propagation to external systems, churn workflows, payment processing, customer support request handling, and more.