(right) up your alley American adjective phrase informal
Being perfectly suitable for one's interests or abilities
Jasmine really loves children, so being a kindergarten teacher would be right up her alley.
With 10 years of experience in accounting, the position of an accounting manager is right up Jennie's alley.
Bean thought that art club is right up his alley, however, he realized he doesn't love it that much.
I really love spicy food, so Thai dishes are right up my alley.
1. (Said of clothing items) To fit perfectly.
2. To be suitable for someone.
The best person or the best thing of a group in which none is good.
1. Of clothing, to have been specially made to fit a particular person.
2. To be perfectly suitable for something or someone.
Used to describe a person who has the necessary qualities for a specific role, task, organization, etc.
'Right up your alley' is used as an adjective phrase in the sentence, therefore, it should be used after 'to be'.
There is no definite origin of the expression although the first recorded usage of the metaphorical usage of the American expression dates to 1931. It can be found in M.E. Gilman’s Sob Sister v.65 and reads “it’s about time a good murder broke, and this one is right up your alley.”
The first usage of the British English expression can be traced back earlier than its American equivalent to the year 1929. This can be found in the Publishers’ Weekly magazine and reads “A great many of the books published today are, as the saying is, right up her street.”