SDE-1 foundations
You have 0 to 3 years of experience, or this is your first system design round.
50 steps, about 14 h 50 min. 31 lessons, 7 trade-offs, 12 practice steps.
SDE-1
Tracks
Pick a path. Follow it in order.
Each track puts lessons, trade-offs and practice in a useful order, with a mock interview at the end. You can read the lessons and guides free. Some practice steps need a free account or use an AI mock. Each track shows an estimated time; yours will vary.
Choose one
Which track is yours?
Start with the level you are preparing for. You can move to the next track when you finish.
SDE-2 system design
You have about 2 to 6 years of experience and you know the basics of caches, databases and APIs.
51 steps, about 17 h, not counting incident investigation. 26 lessons, 9 trade-offs, 16 practice steps.
SDE-2
Senior system design
You have about 5 years of experience or more, and you are preparing for senior rounds.
62 steps, about 23 h 30 min, not counting incident investigation. 26 lessons, 12 trade-offs, 24 practice steps.
Senior
Staff: architecture and trade-offs
You are a senior engineer who is aiming for Staff, or you lead designs and want to defend them well.
41 steps, about 10 h 40 min, not counting incident investigation. 17 lessons, 13 trade-offs, 11 practice steps.
SeniorStaff
Machine coding and low-level design
You have a machine coding or low-level design round coming, and you want a clear order to prepare in.
41 steps, about 25 h 30 min. 22 lessons, 3 trade-offs, 16 practice steps.
SDE-1SDE-2
AI engineering system design
You build or will build features on top of a large language model, and you want to design them well in an interview.
23 steps, about 7 h 20 min. 11 lessons, 4 trade-offs, 8 practice steps.
SDE-2Senior
SQL for interviews
You have a SQL round coming, or you want to write queries with more confidence.
20 steps, about 6 h 20 min. 13 lessons, 3 trade-offs, 4 practice steps.
SDE-1SDE-2Senior
Interview craft
You can solve the problems, and you want to get better at telling your stories and running the round.
13 steps, about 5 h 40 min. 9 lessons, 0 trade-offs, 4 practice steps.
SDE-1SDE-2Senior
Estimates
How we count the time
These times are planning estimates, not deadlines. Yours will vary.
- Lessons and trade-off pages: the number of words divided by 130, rounded, plus 4 minutes to think.
- A Drill: about 7 minutes. A system design mock: allow about 45 minutes. A machine coding mock: allow about 75 minutes.
- Other mocks: a SQL mock with one problem, about 29 minutes. A behavioural mock, about 36 minutes. A resume mock, about 35 minutes. A coding mock, about 45 minutes.
- A simulator level or a Cost Lab workload: allow about 15 minutes. This is our own estimate for a first try. It can take you less or more.
- Incident investigation: time varies. The room has a simulated clock; your real time depends on how you investigate. It has no fixed time, so it is not counted in any total.
- The total is the sum of all steps that have a time. The weeks are the hours divided by 4, rounded up. We assume 4 hours a week, like a person with a job. Doing a step again is not counted.
Not sure where to start?
Try the free load simulator: all 8 levels, no account, no AI.