Optimizing Alert Efficiency: A Comprehensive Guide to Notification System Design for Software Developers and System Designers.
💁♂️Mastering Notification System Design in 45 Minutes 👑
Are you ready to dive into the fascinating world of Notification System Design? In just 45 minutes?
🎯 Objective
The primary goal is to design a notification service capable of sending product-to-user notifications seamlessly across multiple channels while overcoming common challenges.
Here are the core requirements:
1. Send API: Establish an authenticated endpoint to trigger notifications from various backend and microservices.
2. Supported Channels: Support notification delivery through diverse channels like Email, SMS, and Push notifications.
3. User Preferences: Empower users to personalize their notification preferences for each channel and notification type.
4. Respecting Service Limits: Ensure compliance with downstream service limits (e.g., email or SMS providers) to prevent throttling or suspension.
5. Scalability: Enable horizontal scaling to accommodate potentially unlimited growth.
👉 A Quick Overview
Let’s walk through a high-level overview of how this notification system works:
1. Your application calls the `/send` endpoint with details such as the
recipient’s userID.
2. The `/send` endpoint authenticates the request using OAuth2’s Client Credentials Flow.
3. It fetches the user’s notification preferences from the database to determine their subscriptions.
4. User attributes, such as email addresses or phone numbers, are retrieved from the database.
5. The endpoint constructs a message object containing user attributes and content for each channel, excluding disabled channels.
6. This message is sent to a fanout service, which distributes it to specific job queues based on the target channels.
7. Each channel has its job queue and processor. Processors pick up jobs and request the corresponding service (e.g., transactional email or SMS) for notification delivery.
🌟 Important Architecture Decisions
Key architecture decisions to note:
- The `/send` endpoint only requires the `userID`, ensuring services that send notifications have no knowledge of user-specific data.
- Load balancing ensures scalability and availability of the `/send`endpoint.
- OAuth2 Client Credential Flow secures the endpoint for server-to-server communication.
- User preferences are stored in a highly scalable NoSQL or key-value pair database.
- Fanout efficiently duplicates messages for different channels.
- Job queues and processors handle message processing, allowing asynchronous, controlled, and reliable delivery.
- Job processors make API calls to external services for notification delivery.
📈 Why Job Queues and Processors?
Job queues and processors serve multiple vital purposes:
A) External delivery services can be slow, and queues enable asynchronous processing.
B) Queue mechanisms control job rates, preventing throttling.
C) In case of external service outages, job queues provide error handling without code modifications.
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