The Woo.

The Woois the pseudonymous author of How To Quant. Career Notes are written under this name. The real name isn't important — what matters is the math.

How To Quant teaches the contents of A Practical Guide to Quantitative Finance Interviewsby Xinfeng Zhou (the "green book"). The book is canonical; the site is opinionated about how to teach it.

The thesis: most quant interview prep is shallow. Read the problem, peek at the answer, move on. That doesn't stick. Streaks do. Writing out your reasoning does. So this site has both.

No subscriptions. No ads. No data sold. £5 lifetime gets you everything; free gets you the daily-unlock flow. The math is the same; the pace is what changes.

The site runs on a single Oracle Cloud always-free VM. Built by one person. Maintained by one person. If it breaks, it breaks — but the math stays correct.