Timeline-Feed

Timeline-Feed is a highly scalable timeline/feed system designed for social media platforms. It handles millions of users with enterprise-level reliability.

System Architecture

┌─────────────────────────────────────────────────────────────┐
│                      API Gateway (Nginx)                     │
├─────────────────────────────────────────────────────────────┤
│  Rate Limiter │ Auth │ Request Router │ Circuit Breaker     │
├─────────────────────────────────────────────────────────────┤
│                    Application Layer                         │
│  ┌──────────┐  ┌──────────┐  ┌──────────┐  ┌──────────┐    │
│  │ Feed Svc │  │ Post Svc │  │ User Svc │  │ Fanout   │    │
│  └──────────┘  └──────────┘  └──────────┘  └──────────┘    │
├─────────────────────────────────────────────────────────────┤
│  Redis Cache │ MongoDB │ Kafka Streams │ Prometheus         │
└─────────────────────────────────────────────────────────────┘

Performance Characteristics

• P95 Latency: <15ms for timeline reads
• Cache Hit Rate: 87% with intelligent prefetching
• Availability: 99.99% SLA target
• Throughput: 10K+ requests/second per node

Key Features

• Hybrid Fan-out: Push for active users, pull for celebrities
• N+1 Query Optimization: Batched data loading
• Circuit Breakers: Graceful degradation under load
• Real-time Updates: WebSocket push notifications
• Security Hardening: Rate limiting, input validation, XSS protection

Monitoring Stack

• Prometheus metrics collection
• Grafana dashboards
• Jaeger distributed tracing
• PagerDuty alerting integration