Memgraph is an in-memory graph database designed for real-time analytics on streaming data. Instead of storing data in tables, you store it as nodes (entities) and edges (relationships). When new events arrive (user purchase, login, transfer), you ingest them into the graph and immediately query it for patterns. Example: fraud detection. A transaction arrives. You query: "Is this user connected to known fraudsters within 3 hops?" Memgraph answers in <50ms. You trigger an alert. Repeat for 10K transactions/second. Traditional databases can't keep up; graph databases excel at this.