This document discusses how Shopify uses Apache Kafka in their systems architecture. It describes how Kafka provides reliable asynchronous messaging that allows Shopify to collect logs and events and feed them to their data lake. It outlines how Kafka provides operational decoupling and allows them to deploy application or Kafka changes independently. It then discusses two specific use cases: using Kafka as part of a logs/events pipeline and using it to enable active-active Elasticsearch replication across multiple data centers.