I applied online via their portal. A few days later I got a screening call from a recruiter who previously never replied to me re. what format the call would be. Then I was invited to do their online questionnaire/behaviour assessment which is largely about Barclays values and what you'd do in certain scenarios, nothing technical.

After that I was invited to an interview, which was basically another screening call but more technical. I had not been told before what the interview would be, so I had no idea how to best prepare. That person informed me there would be two more stages: 1) a technical interview based on an exercise I'd be given, and 2) a behavioural/culture fit. They put me forward, yet the (new) recruiter initially rejected me and followed up with an email and phone call to say I was put forward, it was a rejection in error.

Less than 48 hours before the next interview, I received the details for the exercise, which seemed easy enough to do, yet not clearly defined/limited; one note said to consider all the things you would for a production application, which is very open-ended and could quickly turn into hours of work depending on how far you go, which is time no one has with such short notice.

I thought the interview went well but after a nearly 3 week wait, I was rejected with no reason or feedback. Their rejection letter says you can ask for feedback from the recruiter, but that person hasn't replied to me and I doubt they will. It is the same person that rejected me in error previously. They and their colleague from the first call both seem very unprofessional.

It was a long-winded and intransparent process.

Stateless versus stateful.

Horizontal scaling.