We are building a system that keeps both customers and internal staff instantly informed, and we need a seasoned back-end developer to own the server-side logic that makes those alerts happen. The core of the job is to design, code, and later maintain an API-driven service capable of firing off time-critical notifications (email, SMS, push, or any channel you recommend) as well as routine account and order updates. Here’s what we are looking for: • Architecture & coding: set up a robust, secure, and easily extensible back end language and framework are flexible as long as you can justify the choice and prove it scales. • Delivery engines: integrate with providers like SendGrid, Twilio, Firebase, or similar so messages reach the right device in milliseconds. • Update orchestration: implement logic for transactional events (order status changes, password resets, etc.) plus scheduled or rule-based promotional blasts without cross-talk or duplication. • Reliability: queueing, retries, rate-limiting, and graceful fallbacks are must-haves. • Observability: logs, metrics, and alerting that let us trace every message from trigger to delivery. • Tests & docs: unit tests around critical flows and clear README/API reference so other devs can plug in fast. Deliverables will be: 1. Source code in a Git repo with commit history. 2. A running demo (Docker, serverless stack, or cloud instance). 3. Setup and operating guide. If you’ve built similar real-time notification pipelines before and can point to measurable uptime and throughput, let’s talk.