Architecture

CQRS

Command Query Responsibility Segregation: separate models for writes and reads.

Why interviewers ask about it

Independent of event sourcing, though often paired. Worth it when read and write workloads differ dramatically in shape or volume.

Store the immutable log of events as the source of truth; current state is a projection of it.

This term is part of the free System Design interview preparation module - browse the full glossary for every definition.