---
title: "Module Overview: Real-Time Systems"
weight: 0
summary: "Design for low-latency, streaming, and event-driven architectures."
---

# Module Overview: Real-Time Systems

**"Design a system that updates users in real time."**

This module covers real-time patterns: event streams, fanout, ordering, backpressure, and operational trade-offs.

## Learning Goals

- Choose between polling, webhooks, and streaming
- Model event-driven architecture with clear boundaries
- Reason about ordering, retries, and idempotency
- Design for latency, throughput, and cost simultaneously

## Interview Preparation

- ✅ Explain push vs pull trade-offs
- ✅ Discuss pub/sub, partitions, and consumer groups
- ✅ Handle retries, duplicates, and ordering guarantees

## Real-World Application

- Notifications and activity feeds
- Realtime dashboards and collaboration
- Streaming pipelines and event processing

## Estimated Time

45-60 minutes (includes practice)

## Checklist

- [ ] Can explain polling vs push vs streaming
- [ ] Can model event streams and consumers
- [ ] Can design idempotent handlers and retries
