Found out about these puzzles from this efinancialcareers article from July. Going back and looking at some of the older ones when I have time.
The puzzle site is here https://www.janestreet.com/puzzles/current-puzzle/
A good tableau based league table is here https://public.tableau.com/app/profile/heidi.stockton/viz/PuzzlesofJaneStreet/JaneStreet