Event-Driven

Previous Chapter: Part 1 — Microservices & GitOps Blueprint | Series Hub | Next Chapter: Part 3 — Data Infrastructure: From Aurora to TiDB Answer-first: PayPay guarantees zero event loss and strict ledger decoupling under promotional surges exceeding 1,250 TPS by combining the Transactional Outbox pattern with Debezium CDC and Apache Kafka. Consumer groups utilize the CooperativeStickyAssignor to prevent rebalance stop-the-world pauses, while a two-stage Redis distributed lock provides exactly-once processing semantics before persisting updates into the database. ...

Series Navigation: This is Part 3 of the Core Banking Systems Architecture Masterclass. ← Previous: Part 2 — Distributed SQL ACID Latency | Master Curriculum Hub | Next: Part 4 — Saga Pattern → | Pillar Hub: Banking Microservices Architecture Event Sourcing & CQRS: Immutable Ledger for Microservices Answer-first: Event Sourcing and CQRS resolve the fundamental architectural tension in core banking between immutable auditability on the write path and ultra-low latency on the read path. By treating append-only domain event streams as the single source of truth and publishing via NATS JetStream transactional outbox pipelines, core platforms eliminate dual-write hazards and achieve sub-millisecond balance projection latencies. ...