Rakuten Devops Engineer interview questions

Worst Interview Experience I ever had in my professional life. - Applied through employee referral, got 2 first rounds as online coding/MCQ rounds - After this, went through 3 subsequent interviews (you can't proceed unless you qualify the previous one). First 2 as technical and the final round as HR, just asking normal questions. I was confident to get in and even my referrer congratulated me that I am in. - This whole process took almost more than 1 month, after which the most troubling thing happened. They ghosted me for 3 weeks after the final round, no communication at all. - Then suddenly their HR member calls me asking details on Name, Visa, and other stuff. I said Ok, must be related to offer letter. - After 3 more days, the most bewildering thing happens which I have never experienced in my whole life. Here I am expecting an offer letter from them, and they reply that they won't be hiring me, without any reason. - I am extremely shocked since all the interviews were over with positive feedback from all of them, and now they suddenly, randomly, just decide to reject me. After mailing, they say "internal HR manager" discussion (who have no idea about my interviews at all, wonder on what grounds did they make their decision). All in all, they wasted more than 2 months, took 5 rounds and wasted everyone's effort involved in the process including me and the interviewers and finally rejected without any reason, citing internal HR manager's discussion. This was my worst experience yet, not only interview-related but overall as well. My whole effort and time was wasted over these last 2 months. I won't wish the experience I had even on my worst enemy. Sincere advice: Don't apply at Rakuten. DON'T, even if you are desperate. You can qualify through all the rounds with flying colours and still get a hard, cold rejection instead of an offer letter in the end.