Event Sourcing with CQRS in Mobile Backends: Building an Audit-Complete Order System with PostgreSQL and Kafka

--- title : " Event Sourcing with CQRS: Build an Audit-Complete Order System for Mobile Backends" published : true description : " A hands-on guide to implementing event sourcing with CQRS using PostgreSQL and Kafka — with concrete schemas, snapshotting, and the failure modes that actually bite you in production." tags : architecture, kotlin, postgresql, api canonical_url : https://blog.mvpfactory.co/event-sourcing-cqrs-mobile-backends --- ## What We Will Build By the end of this tutorial, you will have a working event-sourced order system for a mobile backend. We will design a PostgreSQL event store, set up CQRS with purpose-built projections for mobile reads, wire in Kafka for async processing, and add snapshotting so aggregate replay stays fast at scale. Let me show you a pattern I use in every project that handles orders, payments, or anything with audit requirements. ## Prerequisites - PostgreSQL 16+ - Apache Kafka (or a managed equivalent like Confluent Cloud) - Familiarity with