Questions that adapt to you
Per-topic skill scores: nail TCP and TCP gets harder, miss DNS and DNS eases off.
Know your sh*t.
Top quant and infra teams don’t just test your LeetCode. They ask what a page fault is, why TCP waits in TIME_WAIT, and how you’d design an order book. One session a day until you know it cold.
On the list
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One email when it launches. No spam.
10 tracks600 questionsGraded answers1 session a day
Instructions to candidates
- Answer one session a day. Multiple choice, flashcards and explain-it questions, pitched at your level per topic.
- Show your reasoning. Explain answers, typed or spoken, are graded against the rubric a real interviewer uses.
- Learn from every mark. Each question ends with a plain-English explainer, a deep dive and the follow-up they’d ask next.
- Wrong answers come back. Misses return in ten minutes, then on a spaced schedule until they stick.
Section A · Try it
Do you actually know?
Question 1Networking · [4 marks]
Pick one.
Question 5Explain it · [10 marks]
Why does a TCP connection sit in TIME_WAIT for 2×MSL after closing?
Candidate’s answer
So the connection doesn’t close too early. It waits in case the final ACK gets lost and has to be sent again.
- ✓Re-sends the final ACK if the peer retransmits its FIN+4
- ✗Lets stray segments from the old connection expire before the port pair is reused0/4
- ✗Only the side that closes first waits0/2
Half the story. Why 2×MSL? See me.
4
Section B · Syllabus
The deep end, organized.
Ten tracks written for quant, HFT and infrastructure loops. Every question fact-checked before it ships. Open a track to see what’s on the paper.
Section C · Inside the app
One session. Every day.
AI writes the code now. Interviewers still ask what a page fault is. This drills the knowledge round, the part LeetCode never covers.
Know exactly why
A plain-English explainer, a deep dive, and a rubric that shows what you skipped.
Streaks, XP, rankings
A weekly leaderboard that resets every Monday, and a live room to race your study group.
Section D · Never lost
Never heard of it? Ask Gary.
Most people get the first question wrong because nobody explained the basics. So before you answer, Gary or Tyler offers the 30-second version, in plain words, with a picture.
Need context?
New topic? They pop in before you answer. Tap them for the background, never the answer.
In their own words
A short explainer, a diagram, and the key terms, written for someone who's never seen it.
Free beginner courses
Computers, Linux, Git, the internet and AWS. A lesson first, then the questions.
Section E · The tutor
Got it wrong? Ask why.
Every question comes with an explanation. When it still doesn’t click, ask the tutor. It knows exactly what you just answered, and when a picture helps, it draws one you can poke.
- Plain English first. The intuition in a few sentences, then the real numbers.
- Follow-ups. “Simpler.” “Give me a real example.” Short answers, no lecture.
- It draws. Live diagrams built for your exact question, animated step by step.
Sequence diagramsMemory layoutsState machinesData structuresFlowsCharts
TutorNetworking · Load balancing
What does an ALB actually do?
It sits in front of your servers and spreads requests across them. It works at layer 7, so it can route by path or header, and health checks pull dead servers out of rotation. Watch:
Round robin hands requests out in turn: a, b, c, a, b, c…
Section F · The map
Every gap, closed.
Interviews don’t stay in one lane. A TCP question turns into a kernel question, then a latency question. So the content is a graph: every topic linked to where an interviewer goes next. Tap a track. Dashed nodes are being written now.
59 topics live18 in the worksCross-track links
Section G · Live rooms
Play live with friends.
Spin up a room, share the code, and race your study group through the same questions on the same clock.
- Fastest right answer wins. Points for correct, bonus for quick.
- Any track or topic. 5 to 15 questions, 10 to 30 seconds each.
- Live standings after every question, podium at the end.
Section H · Also permitted
Allowed in the exam room.
✓
Say it out loud
Answer explain questions by voice, like you would in the room. Graded against the same rubric.
✓
Spaced review
Everything you missed in one place, coming back on a schedule until it sticks.
✓
A countdown
Set your interview date and your prep paces itself to it. Reminders know what you’re weak at.
✓
System design & behavioral
Full interview rounds: estimates and trade-offs, plus “tell me about a time” without the rambling.
✓
A two-minute placement
A quick adaptive test per track sets where you start. Or skip it and start from zero.
Section I · Your examiners
Meet the panel.
Senior infra engineer
Gary
Twelve years on call. Has heard your answer before. Will explain it once, slowly, with a sigh.
“It’s three messages. Sit down.”
Candidate · interview tomorrow
Tyler
Fully cooked on Monday. Knows his sh*t by Friday. Asks the questions you were too scared to.
“Wait. That’s it?!”
Everyone’s cooked. Except you.
Get on the list and be first in when Know Your Sh*t launches on iOS.
On the list
You’re in.
One email when it launches. No spam.