Netflix Streaming Architecture

Explore Netflix's streaming architecture, CDN strategy, and how they serve billions of hours of content globally.

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Architecture Evolution

Netflix's transformation from monolith to microservices happened gradually over 9 years, driven by scale and the need for rapid innovation.

1

Monolithic DVD

2007-201010M subscribers

Single Java application

Key Challenge: Limited scalability, slow deployments
2

Cloud Migration

2010-201340M subscribers

Lift and shift to AWS

Key Challenge: Learning distributed systems
3

Microservices

2013-201680M subscribers

500+ microservices

Key Challenge: Service coordination, monitoring
4

Global Platform

2016-Present230M+ subscribers

1000+ microservices

Key Challenge: Global consistency, personalization

Core Platform Services

Netflix built and open-sourced many foundational microservices components that became industry standards.

Zuul (API Gateway)Java, filters
Purpose:
Route requests, authentication
Scale:
2M+ requests/sec
Eureka (Service Discovery)REST, heartbeats
Purpose:
Service registration/discovery
Scale:
10K+ services
Hystrix (Circuit Breaker)Bulkhead pattern
Purpose:
Fault tolerance, isolation
Scale:
Latency < 99th percentile
Ribbon (Load Balancer)Java, algorithms
Purpose:
Client-side load balancing
Scale:
Dynamic server lists

Content Delivery at Scale

Global CDN Performance

Cache Hit Rate
5%Origin
95%Edge
Response Time
200msOrigin
20msEdge
Bandwidth Cost
100%Origin
10%Edge

Content Strategy

Popular Content
Predictive caching for trending shows
100% Pre-cached
Long Tail Content
Generated on first request
On-demand
Live Events
Sports, award shows
Real-time

Encoding Pipeline

Multiple Bitrates
240p to 4K, adaptive streaming
Global Distribution
15,000+ servers in 200+ countries

Personalization at Scale

Data Collection

• 500+ billion events/day
• Viewing patterns, searches
• Device types, time of day
• Pause, rewind, fast-forward

ML Pipeline

• Collaborative filtering
• Deep learning models
• A/B testing framework
• Real-time inference

Results

• 80% of viewing from recs
• 2M+ A/B tests/year
• Sub-second response
• Personalized artwork

Recommendation Performance

Homepage Response
Personalized for 230M+ users
< 100ms
Model Training
Continuous learning from new data
Daily
A/B Test Impact
Typical engagement improvement
2-10%

Key Architectural Lessons

What Worked

  • • Gradual migration over years, not big-bang
  • • Investment in observability and tooling first
  • • Culture of experimentation and failure tolerance
  • • Service ownership by small teams
  • • Open-sourcing for community feedback

Challenges

  • • Distributed system complexity
  • • Service dependency management
  • • Debugging across 1000+ services
  • • Data consistency across services
  • • Operational overhead and tooling

📝 Case Study Quiz

Question 1 of 4

What was Netflix's primary challenge when moving from a monolithic architecture to microservices?