Notification Hub

One place to compose, template, queue and deliver messages across every channel. Channels sit behind a provider abstraction whose default is a zero-external-call console provider; a channel whose real provider is unconfigured degrades to it gracefully. Templates are versioned with {{variable}} interpolation, and the message queue retries with backoff and dead-letters after exhausting attempts.

Responsibilities

• Channels for email, SMS, push, Slack, Teams, Discord and webhooks
• Provider abstraction with graceful degradation to a console no-op
• Versioned templates with variable interpolation and HTML escaping
• Retryable message queue with backoff and dead-lettering
• Idempotent sends; a preview endpoint that renders without sending

API surface

• POST /api/send
• GET/POST /api/channels
• GET/POST /api/templates · POST /api/templates/:key/preview
• GET /api/messages · POST /api/messages/:id/retry
• POST /api/tick

CONSUMED BY Any module that needs to notify a person or an external system. A Platform Service never depends on a Business Module.