Learn the core building blocks behind scalable systems. Start with the fundamentals, understand how they work, and see how they're used to build applications that grow from hundreds of users to hundreds of millions.
Real-time, full-duplex communication over a single connection
Content Delivery Networks cache static assets at edge servers close to users
Distributing traffic so no single server drowns
Protecting your system from being overwhelmed by requests
Distributing keys across nodes with minimal reshuffling
Breaking a monolith into small independently deployable services
Add more machines instead of upgrading one — scale out, not up
Store frequently accessed data closer to where it is needed
SQL vs NoSQL — choosing the right data store
Splitting data across multiple databases for scale
Consistency, Availability, Partition tolerance — pick two
Copying data across multiple nodes for reliability and speed
Async communication between services that decouples systems
