Start here
Easiest first. Each lesson is a few short chapters, one screen at a time, with a quick check at the end of each. Chapter 1 is open to everyone; when you finish, the next system is one click away.
Fundamentals
The building blocks every system is made of, from the basics to the advanced.
Messaging
→Chat, calls and real-time delivery to billions of phones.
Social networks
→Feeds, follower graphs and the celebrity problem.
Video, music & media
→Streaming, encoding and getting bytes close to every viewer.
Gaming
→Millions of players, live, at the same time.
Payments & fintech
→Moving money: authorizations, ledgers and never charging twice.
Banking & markets
→Exchanges, banks and systems where a millisecond is money.
E-commerce & retail
→Carts, inventory and surviving the biggest sale day of the year.
Ticketing & events
→Selling a fixed number of seats to millions of people at once.
Travel & hospitality
→Search, availability and bookings across the world.
Mobility & delivery
→Matching riders, drivers and orders in real time, on a map.
Search & maps
→Indexing the world and answering in milliseconds.
Cloud & infrastructure
→The storage, databases and schedulers everything else runs on.
Security & identity
→Protecting systems — and what happens when protection breaks.
Productivity & dev tools
→Collaboration, sync and the tools developers live in.