Architecture

Event Sourcing

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

Why interviewers ask about it

Costs schema versioning forever, replay time, snapshots and GDPR complexity. Most teams wanting 'history' actually want an audit-log table.

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

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