the notebooks

Study Notebooks

Long-form manuals on the backend work that interviews and production both care about. Each one is built around a single question, because one question worked properly teaches more than a survey does. Written to be printed and written on.

notebooks: 8
pages: 681
editions each: 3

Every notebook is free to read for 7 days. Sign in, open the one you want, and download all three editions. Nothing is withheld and there is nothing to pay.

Study Notebook / 00
Question Bank
234 prompts pulled from notebooks 01 to 07, answers at the back
Work in pen. A prompt you can only half answer is the whole point of the exercise: mark it, and go back to the section it names. Generated from every other notebook, so it stays in step with them.
135 pages3 editions
System Design Notebook / 01
Large-Scale Data Ingestion
How to accept, store, process and track multi-gigabyte jobs without losing them
Accepting a multi-gigabyte upload is not a bigger version of accepting a form. This one walks the whole path: presigned URLs, multipart and resume, the outbox pattern, the queue, and how a caller finds out the job is still alive.
68 pages3 editions
System Design Notebook / 02
Object Storage
Why a file is not your application's data, and what to do about it
Seven ways the obvious design dies, one at a time, then block, file and object storage compared on what they actually promise. Ends on the trade you are making when you pick one.
86 pages3 editions
Code Review Notebook / 01
Full-Stack Code Review
Nine broken snippets, the defect class behind each, and what a senior engineer says out loud
A five-pass method you can run on unfamiliar code under time pressure, then nine real defects: dropped errors, unowned timers, unparsed input, routes that answer three times. Each one names the class, not just the fix.
76 pages3 editions
Study Notebook / 04
Postgres
Schema, queries and indexes for people who have to keep the thing running
Types, constraints, relationships and indexes, then the part most courses skip: transactions and isolation, the N+1 problem, connection pooling, EXPLAIN, and vacuum. A schema you can draw is table stakes.
71 pages3 editions
Study Notebook / 05
Backend Security
Where you made an assumption, and who is going to find it
Every vulnerability is an assumption someone else found first. Injection across SQL, NoSQL and the shell, password storage done properly, sessions and tokens, and the boundaries where data turns into code.
55 pages3 editions
Study Notebook / 06
Scaling and Performance
Where the time actually goes, and how you know
Latency is a distribution, not a number. Measure before you fix: percentiles, utilization and the knee, flame graphs, distributed tracing. Then the fixes, in the order they pay off.
100 pages3 editions
System Design Notebook / 07
Real-Time Backends
What it costs to let the server speak first
Polling, long polling, SSE and WebSockets, priced honestly. The proxies that eat your stream, the six-connections-per-origin limit, and what any of it does to a server you have to keep running.
90 pages2 editions

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Study Notebooks

Question Bank

Large-Scale Data Ingestion

Object Storage

Full-Stack Code Review

Postgres

Backend Security

Scaling and Performance

Real-Time Backends

Read them with other people