The interview process could be improved here. I was recommended by a friend and Spotify employee to their internal recruiter. We had a call, followed by an in-person interview, and then I met with two members of senior staff who seemed excited about our conversation and the possibility of working together.
I was promptly called and asked to return. On that day, I interviewed with two designers, completed an exercise with two developers, and then interviewed with another senior staff member. By that last interview, I was exhausted, and unfortunately it seemed like an important one. I then had one more meeting with their internal recruiter about salary expectations, and we spoke in a manner that felt like I could expect an offer in that range.
I sent personal thank you notes and after a week passed, I dropped the recruiter a note to ask if they were close to making a decision. He indicated I was the top candidate, but one person who still needed to weigh in was on vacation. After another week passed, that person called to say he was really impressed with me, but the project he wanted to hire me for had been put on hold indefinitely.
It was unexpected and I was definitely disappointed.
My advice to Spotify would be to reduce the number of interviews by teaming people up in twos, or to split interviews up over more days. I've done both while interviewing potential hires. It keeps energy levels high, and reduces the number of times candidates have to answer the same questions.
And if a budget or project hasn't yet been approved for the hire, tell them so. They may be delaying acceptance of other offers and interviews, because Spotify is a fantastic place to work!