DeltaStream is a serverless stream processing platform designed to handle, secure, and process data streams on the cloud. The platform facilitates the creation of materialized views that continuously update in real-time based on streaming queries, allowing users to access up-to-date results with sub-second latency. These materialized views are built from event streams created in platforms like Apache Kafka, and can be queried like traditional SQL tables. The post demonstrates the creation of three types of materialized views: counting URL visits, tracking visits by device type, and monitoring user visits across devices. These examples illustrate how DeltaStream streamlines the process of transforming raw streaming data into actionable insights that can be served to users via a web interface, promising future enhancements in real-time application development and management.