Notification Service (Node.js, Redis, BullMQ, SendGrid, Twilio, PostgreSQL) overview

A multi-channel notification service that delivers email, SMS, push, and in-app notifications through a unified API. BullMQ manages job queues in Redis for reliable delivery with retry logic, rate limiting, and priority scheduling. SendGrid handles transactional and marketing email while Twilio provides SMS and voice channels. PostgreSQL stores notification logs, user preferences, and delivery receipts. TypeScript ensures type-safe message templates and channel routing rules. Designed for product teams that need a centralized notification backbone rather than per-feature ad-hoc delivery. The tradeoff is queue monitoring overhead and the complexity of managing delivery SLAs across multiple providers.