OLL 30
The algorithm, how to recognise it and how to practise it without cheating.
Recommended algorithm
F R' F R2 U' R' U' R U R' F211 moves
How to recognise it
Yellow on top: the back and left edges and the two front corners. The back corners' yellow faces left and right.
Its inverse is another case
Do the 30 algorithm backwards, F2 R U' R' U R U R2 F' R F', and you are solving 45.
That's why CubeDojo never scrambles 30 that way: it builds a random state with the case fixed, so you practise 30 and not 45.
Practise 30 now
Random-state scrambles, a timer and spaced review. Free, on the web and on your phone.