How the apps you use every day stay fast and stay up
When engineers say “we need a cache” or “the database has to be sharded,” this course is for the people in the room who want to follow along. No coding background needed. Just clear pictures, the real words, and why they matter.
// How each lesson will work
Built for people who don’t write code
Everyday picture first
Every idea will start with something you already know: a queue at a coffee shop, a library index, a front desk.
Then the real word
Once the picture makes sense, you will get the term engineers actually use, so you can follow the conversation at work.
Why it matters to you
Each lesson will end with the trade-off in plain terms: what it costs, what it buys, and the question worth asking your team.
// Syllabus
Twenty-five ideas, in five steps
Each step builds on the one before it. The first step is free for everyone. The other four steps make up the $29 full course, which is opening soon. The five Foundations lessons are ready to read now. The rest are still being written, so their rows don’t open yet.
- Tier 1Foundations5 lessons · Free
- Tier 2Speed & staying up5 lessons · Full course
- Tier 3Data6 lessons · Full course
- Tier 4Services talking6 lessons · Full course
- Tier 5Safety3 lessons · Full course
// Tier 1
Foundations
The basic words engineers use when they talk about speed and size.
How long one request takes to come back: the wait you feel after you tap a button.
FreeHow much work a system finishes each second, and why that is not the same as speed.
FreeWhat it takes for a system to keep up when ten times more people show up.
FreeHow a name like mirquadri.com turns into the address of a real computer.
FreeSpreading visitors across several servers so no single one gets crushed.
Free
// Tier 2
Speed & staying up
How big sites stay quick, and keep working when something breaks.
Caching
Keeping a copy of an answer close by so you do not have to work it out twice.
Full courseOpening soonCDNs
Serving files from a computer near each visitor instead of one far-away origin.
Full courseOpening soonHigh availability
Designing a service so it stays up even when some of its parts go down.
Full courseOpening soonFault tolerance
Expecting things to break, so one failure does not take everything else with it.
Full courseOpening soonReplication
Keeping copies of the same data on several machines, and what those copies cost.
Full courseOpening soon
// Tier 3
Data
Where information lives, and the trade-offs in keeping it safe and correct.
SQL vs NoSQL
Tables with strict rules versus flexible documents, and how to choose between them.
Full courseOpening soonACID transactions
The four promises that stop a bank transfer from losing money halfway through.
Full courseOpening soonIndexing
A database's version of the index at the back of a book: find things without reading every page.
Full courseOpening soonSharding
Splitting one huge database into smaller pieces that live on different machines.
Full courseOpening soonConsistency models
Whether everyone sees the newest data right away or a little later, and why it matters.
Full courseOpening soonCAP theorem
When the network splits, you choose between always answering and always being right.
Full courseOpening soon
// Tier 4
Services talking
How the separate parts of a large app pass messages to each other.
API design
How to shape the doorway that other programs use to talk to yours.
Full courseOpening soonREST
The most common style for web APIs: things with addresses, and a few plain verbs.
Full courseOpening soonMicroservices
Breaking one big app into small services, and what you gain and give up by doing it.
Full courseOpening soonAPI gateway
One front door that checks and routes every request before it reaches the services behind it.
Full courseOpening soonMessage queues
Letting one part of a system leave work for another part to pick up later.
Full courseOpening soonPub/sub
Announcing something once so every part of the system that cares hears about it.
Full courseOpening soon
// Tier 5
Safety
Knowing who is knocking, what they may do, and how often they may do it.
Authentication
Proving who someone is: passwords, sign-in links and sessions.
Full courseOpening soonAuthorization
Deciding what a signed-in person is allowed to see and do.
Full courseOpening soonRate limiting
Capping how often someone can knock, so one visitor cannot flood the system.
Full courseOpening soon
Where this course stands
The five Foundations lessons are published and free to read. The other lessons are being written now, and the syllabus may still change as the writing goes.
The first tier is free for everyone, and you don’t need an account to read it. The full course is not open yet. When it opens, this page will explain how to join.