I think what has happened is the author has no idea what "email backend" was, so he just decided to ignore that part and build the only backend he knew, web-app backend. And those terms are pretty different. The "email backend" is the service which actually stores and transfers email, in the author's case it was turso + postman.
So from the interviewer's standpoint, author was asking about few details of implementation, like "can I use third-party service for email storage?"; and the response was of course "yes, you can" (because assignment was pretty clear that backend does not need to be advanced or even present, and that it's UI that matters)
I guess the question worked as intended, and filtered out candidate who cannot even read the simple requirements.
(The amount of effort was disproportional though, but I am not sure how to solve this in take-home context without discriminating against people who have busy schedules and/or work slowly)
So from the interviewer's standpoint, author was asking about few details of implementation, like "can I use third-party service for email storage?"; and the response was of course "yes, you can" (because assignment was pretty clear that backend does not need to be advanced or even present, and that it's UI that matters)
I guess the question worked as intended, and filtered out candidate who cannot even read the simple requirements.
(The amount of effort was disproportional though, but I am not sure how to solve this in take-home context without discriminating against people who have busy schedules and/or work slowly)