A couple of weeks after I applied, I was invited to attempt an online IQ test. In quick succession after this test (within 2 days each) were an interview with the HR Recruiter, with the hiring manager and a technical interview with 2 engineers. All interviewers were very professional and highly knowledgeable in their domain. The interviewers were not easy, but the interviewers never put me in a spot or made me feel uncomfortable - and as a result, I was able to do my best.
After this, I was invited for an on-site interview in Stockholm, for which my travel and stay were promptly arranged (I flew in from a non-EU country).
The on-site interviews were also very well organized. They were 4 back to back interviews in the first half of the day. I felt at ease throughout. I especially enjoyed the live-coding test and felt that it is a very good way to test a candidate's skills (as opposed to textbook questions which might serve a candidate's memory at best).
The HR Recruiter always kept me in the loop regarding any updates in my application and in the hiring process. Enjoyed the interviews a lot, and am now looking forward to start working at Klarna!