C4 component diagram for a Communication Module microservice handling centralized notifications, templates, delivery, retries, and external provider integrations on AWS. The architecture receives events from six producer modules (Customer/KYC, Transaction, Statement, Chargeback/Dispute, Regulatory Reporting, Backoffice) via an internal event bus, processes them through a command handler, template manager, recipient resolver, and channel policy engine. Messages are dispatched through a communication gateway adapter to external providers (email, SMS, push) with delivery tracking, retry logic, and dead-letter handling. The module publishes completion events to an audit module and exposes a public API for message status queries, demonstrating event-driven decoupling and scalable notification orchestration.