System Design Interview
system-design-interview
Community
Behavioral Paired With Design: The Bar-Raiser Pattern
A 4-question reconstruction of a bar-raiser loop where every behavioral prompt opened the door for a design follow-up. Each question pairs the story I told with the sketch I had to draw 20 seconds later.
Data Engineer Loop: The SQL Test That Wasn't Just SQL
A data engineering loop at a Series C analytics company. The SQL round looked like a standard SQL test. It was grading something else entirely.
DevOps / SRE Interview: The Production Postmortem Round
An SRE loop at a Series D infra company, anchored on the round where they handed me a real-feeling postmortem and asked me to find what was missing.
Recovering From a Bad Round, Mid-Loop
I bombed round 2 of a 5 round onsite and got the offer. Three loops later I bombed another round 2 and didn't. Here is what was different.
Startup vs. FAANG Interview Differences
I ran a Series B startup loop and a Meta loop in the same month. The shape, the calibration, and what each one was actually grading were nothing alike.
Designing a Feed in 45 Minutes at a Mid-Size SaaS
A senior system design round at a mid-size B2B SaaS where the prompt was a generic activity feed but 45 minutes forced me to commit to a fan-out strategy in the first ten minutes.
London Engineering Loop: What Differs From the US
I ran a London senior engineer loop after eight years in the Bay Area. Comp bands, right-to-work, IR35, and the cultural pieces I had to learn live.
Tradeoff Stories and the Design They Led To
A 5-question set where each behavioral tradeoff story is paired with the design choice it forced. Drawn from a senior backend loop where the interviewer kept pushing past the story into the code that proved it.
The Sysdesign Round Where I Talked Myself Out of an Offer
I drew a clean diagram, then over-explained every tradeoff until the interviewer no longer trusted any of them. A postmortem on a defensible answer that still got rejected.
Series C Hyper-Growth Loop: Speed Over Polish
A Series C hyper-growth loop where the rubric was 'can you ship next week, not in three months'. The shape, the pushback, and the offer that came in 36 hours.
Remote-First Series B Loop: Five Async Rounds
A remote-first Series B ran their entire senior loop async. Three rounds were Loom videos and written replies. Here is how the rhythm and signals worked.
System Design Interview at Stripe
A senior backend system design round at Stripe centered on idempotent webhooks, the failure mode I missed, and how the interviewer pushed me from a clean diagram to a defensible one.
My Take-Home Assignment at a Fintech Company
An 8-hour take-home for a Series B fintech, the design call after, and the one question that decided whether the offer came.
Cloudflare System Design: The Edge-Latency Question
A senior backend system design round at Cloudflare anchored on p99 latency at the edge, where the interviewer pushed past the obvious answers until I had to commit to a defensible number budget.
Disagree-and-Commit Stories With a Design Twist
A 4-question set where each behavioral disagree-and-commit story gets a design follow-up that proves the commit was reversible. The pattern I lean on when an interviewer wants to see both sides of the same call.
Coinbase System Design Round: What "Crypto-Native" Meant
A senior backend system design round at Coinbase where the generic exchange-order-book prompt was actually grading deposit confirmations, double-spend windows, and the cold-wallet boundary.
The System Design Interview Framework I Use in Every Loop
The 45-minute structure I have used as a candidate and the rubric I now use as an interviewer. Sequencing, sample whiteboard, and the 6 common failure modes.
Incident Debrief Questions They Asked Me
A 4-question set drawn from the debrief portion of an SRE-flavored loop. Every behavioral prompt about an on-call story got paired with a design follow-up the interviewer used to stress-test the takeaway.