Senior software engineer in Seattle with 12 years shipping TypeScript at scale, formerly Stripe and AWS. I've run 400+ interview loops and helped 190+ engineers land senior offers.
The 45-Minute System Design Framework
Free download
The Senior TypeScript Playbook
Instant download
Portfolio to Offer: The Engineer's Portfolio Kit
Instant download
System Design Bootcamp: From Whiteboard to Production
Online course
1:1 Mock System Design Interview
60-min 1:1 call
Async Portfolio and Code Review
Custom request
The Merge Queue
Membership · billed monthly
Live Teardown: URL Shortener from Blank Whiteboard
Live · Aug 13
Free 60-minute session: I design a URL shortener from blank whiteboard to production-grade, live, then take open Q&A. 500 Zoom seats - July's session filled in four days, and the replay goes to Merge Queue members only. Registration closes Aug 12 at 23:59 UTC. Grab your free seat below.
Why I teach
I spent 12 years shipping TypeScript at Stripe and AWS, and six of those years interviewing engineers - roughly 400 loops on the other side of the whiteboard. The pattern I kept seeing: strong engineers failing senior interviews not on knowledge but on process, and shipping fragile code not from carelessness but because nobody ever showed them the patterns. Everything on this page is the material I wish someone had handed me at year three. No vendor hype, no framework churn - just the type-level discipline and interview process that compound for an entire career. And if a free resource already covers something, I will point you to the free resource first.
What engineers ship after working with Kai
“I failed two senior loops before finding Kai. After the framework PDF and three mocks, I passed the system design round I had been dreading and signed at L5 - a $74K total comp jump.”
Priya Sharma · Senior Software Engineer, fintech
“The async review found exactly why recruiters ghosted me: six shallow repos and no case study. I rebuilt around one deep project like he said. Three weeks later I had four onsites.”
Marcus Deng · Frontend Engineer
“Lesson 5's Result-type pattern paid for the whole course in one sprint. We adopted it across checkout and our unhandled exceptions dropped about 40% quarter over quarter.”
Elena Rodriguez · Tech Lead, e-commerce startup
Frequently asked questions
I'm self-taught with no CS degree. Is this material for me?+
Yes - about half my students are self-taught. Nothing here assumes a degree: the system design course builds from first principles with arithmetic rather than theory, and the portfolio kit is specifically designed to substitute evidence for credentials. The only prerequisite is that you can build and deploy a basic web app.
What's the difference between the Playbook PDF and the Bootcamp course?+
The Senior TypeScript Playbook is a reference for writing production code; the System Design Bootcamp is training for the interview room (and the architecture work after it). They do not overlap. Interview in the next month? Start with the free framework PDF plus the course. Want your day-to-day code to read senior? Start with the Playbook.
How does the 1:1 mock interview work?+
We meet on Zoom for 60 minutes: 45 minutes running a real prompt exactly like a FAANG onsite, then 15 minutes of debrief where I score you on the same five rubric dimensions companies use. You get the recording and a written scorecard within 24 hours. Evening slots (Pacific) on Monday, Tuesday, and Thursday.
Do you offer refunds?+
Digital products and the course carry a 14-day no-questions refund - email me and it is done. Mock interviews and reviews can be rescheduled up to 24 hours before your slot. The membership cancels anytime and stays active until the end of the billing period.
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