OLL 15
The algorithm, how to recognise it and how to practise it without cheating.
Recommended algorithm
r' U' r R' U' R U r' U r10 moves
Alternatives
(U2) l' U' l L' U' L U l' U l10 moves · with the left hand
How to recognise it
A line through the left and right edges, plus the front-right corner. The front-left corner's yellow faces left.
Its inverse is another case
Do the 15 algorithm backwards, r' U' r U' R' U R r' U r, and you are solving 8.
That's why CubeDojo never scrambles 15 that way: it builds a random state with the case fixed, so you practise 15 and not 8.
Practise 15 now
Random-state scrambles, a timer and spaced review. Free, on the web and on your phone.