Why Netflix, Instagram, and Twitter Pick Different Databases youtube.com

Netflix writes millions of events per second. Instagram scaled to a billion users on PostgreSQL. Twitter serves timelines in milliseconds using Redis.

Three massive systems. Three completely different database choices.
This video breaks down exactly why.

Instead of memorizing tools, you’ll learn how to think like a system designer:
• Why Netflix chose Cassandra for write-heavy workloads
• How Instagram scaled PostgreSQL far beyond expectations
• How Twitter uses Redis for ultra-fast timelines
• The real tradeoffs behind each decision
• A simple framework to choose the right database

If you’re preparing for system design interviews or building scalable systems, this is one of the most important mental models to understand.