Event-Driven

Event Sourcing & CQRS: Immutable Ledger for Microservices Answer-first: Event sourcing and CQRS replace mutable database updates with an immutable append-only event log. Core banking systems record financial state changes as domain events, projecting read models asynchronously while guaranteeing auditability and zero data loss. Pillar Architecture Guide: This article is part of the Architecting 21-Service E-commerce with Golang & DDD series. Please refer to the original article for a detailed architectural overview of the architecture. ...

Executive Summary & Quick Answer: Managing transaction surges during PayPay’s massive marketing campaigns requires event-driven architecture powered by Apache Kafka. Partition key tuning, Go consumer worker pools, and channel-based backpressure prevent message loss during peak traffic spikes. Answer-First: PayPay builds a decoupled microservices network by streaming transactions asynchronously via Apache Kafka. To ensure financial safety, consumers process events using idempotency keys tracked in distributed caches, preventing duplicate ledger entries or double-spend occurrences in the event of retries or network partition splits. ...