What is a materialized view in an event-driven microservices architecture?

A materialized view is a dedicated, pre-combined read model built ahead of time by listening to events, rather than assembled on demand at request time. Instead of a request handler calling several services fresh every time it needs combined data, a listener component subscribes to the relevant events as they happen and merges them into one ready-to-serve record. A request for that data then becomes a single, instant lookup against one table, with no cross-service calls, no request-time composition, and no dependency on every underlying service being available and fast at that exact moment. The trade-off is that the view is eventually consistent, since it's updated asynchronously as events arrive rather than reflecting the absolute latest state at the instant of the read.