TikTok Backend Engineer Interview Questions
& Process

I had two technical rounds and then I was rejected after the second one. Both rounds were structured with the first 15 minutes for introductions, followed by 30-40 minutes of technical problem-solving, and then some time for Q&A. The first round involved a question similar to Daily Temperatures with follow-up questions. In the second round, I was asked two interval scheduling questions.

I applied online and a recruiter contacted me to schedule the first two rounds. They mentioned the second interview depended on how the first one went. Then, my recruiter left TikTok, and a new one took over my case. There was some confusion, possibly due to rescheduling, which resulted in me being marked as a 'Candidate No Show'. After emailing multiple times to clarify, my interviews were rescheduled. It was quite frustrating. The first interview went really well; I felt confident explaining my projects and finished the coding question early, providing correct time and space complexity. Later, I got an email saying I was rejected, even though the second interview invite wasn't canceled as expected. So, I still showed up prepared, but no interviewer appeared. I emailed my recruiter, and they informed me the team chose another candidate without providing feedback.

The interview had 3 rounds. The first round focused on project discussions, specifically about message brokers, different concurrency handling techniques, locks, and data pipeline processing. There was also an easy LeetCode question about reversing a binary tree. The second round involved more project discussion, delving into previous internship experience, and covered a lot of networking and OS questions, particularly memory management. This round also included 3 LeetCode questions: one hard, one medium, and one SQL question. The third round was with the hiring manager, discussing recommendation architecture, and included one long medium algorithm question.