Everything you need to cram for a quant interview, crammed into one HTML file. Cheatsheets, flashcards, and a little lab where you can watch an iron condor lose money in real time. Free, no signup, and you can bend it to your will.
▶ Open the live app · no install · runs in any browser · no, it won't email you
Quant prep is its own unpaid part-time job. The knowledge lives in six different PDFs, two textbooks heavier than your student debt, and a flashcard app that wants $8/month to let you study your own notes.
So I put the whole loop — read it, drill it, simulate it, repeat until it sticks — in a single file you actually own. Open it, study, close it. Your cards, your pins, your progress all stay in your browser. No account. No subscription. No "we've updated our privacy policy" emails at 2am.
Eighteen subjects across five groups — math (calculus, linear algebra, geometry, combinatorics), probability & statistics (probability, distributions, statistics, regression, stochastic processes, time series), finance (options & vol, instruments, microstructure), programming (Python, C++, algorithms), and reasoning (brainteasers, mental math). Bite-size cards with worked examples, because "I knew the formula, I just couldn't recall it under pressure" is not a thing you get to say in the actual interview. One search box covers all of them.
300+ real interview questions (100+ reported from actual quant loops — Glassdoor, Wall Street Oasis, Heard on the Street). Search them, filter by topic, shuffle so you can't cheat by memorizing the order. Flip to check yourself, then pin the ones that humble you, archive the ones you've genuinely nailed, and mark cards done for the session so the pile visibly shrinks. (The dopamine is free too.)
Five tools in one tabbed workbench:
- Payoff explorer — build an option position leg by leg, Black–Scholes-priced, with a live breakeven, max profit/loss, and a P&L crosshair that chases your cursor.
- Distribution explorer — pick from nine distributions (normal, lognormal, exponential, uniform, Poisson, binomial, Student-t, gamma, beta), drag the parameters, watch the density/PMF and analytic moments move, then throw Monte-Carlo samples at it and watch the histogram converge.
- Market maker — a dice market-making game: quote a bid/ask, get picked off by informed flow or paid by noise, and learn the hard way why tight isn't always smart.
- Regression simulator — set a true line, crank the noise, and watch OLS try to find it. R², residuals, the works.
- Python sandbox — run a real simulation in the browser. When the interviewer raises an eyebrow and says "you sure E[flips to get HH] is 6?", you can say "ran it 200,000 times, yeah." That's not arrogance. That's a confidence interval.
- Open the live app — or download
index.htmland double-click it like it's 2005. - Browse — click a subject tile, land on its cheatsheet or flashcards.
- Drill — flip cards, mark done as you go, pin what burns you.
- Experiment — drag the spot/vol/time sliders, build a position, or simulate something to settle a bet with yourself.
- Collect — anything you pin shows up at the top, ready for the night-before panic review.
It's your terminal, so the Workshop lets you:
- Add your own subjects, flashcards, and cheatsheet cards (the question that stumped you in the last round? Add it. Make it pay.)
- Archive, restore, or delete anything
- Everything auto-saves to your browser — no login, because the last thing you need is another password
Want to reskin it or gut it entirely? It's one readable HTML file. Fork it, edit index.html, go nuts.
If you'd rather build your own deck from scratch — no pre-loaded cheatsheets or flashcards getting in your way — open blank.html. Same terminal, same Lab, zero seed content. Everything you add in the Workshop is yours alone. It's generated from index.html by build-blank.py, so it never drifts from the real thing.
Nothing to install — open index.html in any modern browser. The fonts and the Python runtime load from a CDN, so those bits want an internet connection; everything else works on a plane, in a bunker, or during the campus wifi outage right before your mock interview.
This is an early release, not the finished article. More cheatsheets, more flashcards, and more lab toys are coming — the whole thing is data-driven, so most of it shows up as new cards, not a new app. Check back, or ⭐ the repo to get nagged when it grows.
Free for personal, non-commercial use under CC BY-NC 4.0. Study with it, share it, build on it — just give credit and don't sell my flashcards back to me. See LICENSE.
Built by someone who was also prepping for quant interviews. If it helps you land the offer, a ⭐ is a perfectly acceptable thank-you.