What is CQRS in C# Application Architecture?

CQRS, or Command Query Responsibility Segregation, is an architectural pattern that separates operations that change application state (commands) from operations that retrieve data (queries).

Instead of using one model for both reading and writing, a CQRS-based application can have separate models optimized for each responsibility. For example, a command might process an order creation request, while a query might retrieve an optimized order summary for a dashboard.

CQRS can be particularly useful in complex systems where read and write workloads have different requirements, business rules, performance characteristics, or scaling needs.

However, CQRS should not automatically be introduced into every C# application. It adds architectural complexity, so developers should evaluate factors such as domain complexity, scalability requirements, consistency needs, team maturity, and operational overhead.

A good architect knows not only how to implement CQRS using C# and .NET, but also when not to use it.