I've had the misfortune to interview here twice. Background: I'm a recent college grad with 1 year of experience in the industry.

First time:

• They made me code a multiplayer Tic-Tac-Toe game with NodeJS.
• After spending the time and effort on this project, they invited me onsite. They locked me in a room for 2 hours and gave me a project to build onsite. This was very frustrating as I was expecting data structures, algorithms, or system design questions, having already completed the project portion. I felt this was a cop-out, as I expected a traditional whiteboard interview from a company as large as Tinder. An onsite project like this is challenging for typical junior-level developers.

A year later, during my second interview, I aced the phone screen in record time. I was applying for a NodeJS Web Developer position in the Bay Area and made it very clear to the interviewer that I wanted the web development role. Despite this, I received a call from the recruiter the next day stating that I did not pass my interview for the Infra team in LA. I never applied to the Infra team in LA! I tried to correct her, but she did not budge in her decision. Ultimately, I let it go as I had already received multiple offers. Screw this company.

Second interview:

1. A shuffled set contains unique numbers except one of the numbers appears twice. Find the number that appears twice.

(Funny enough, the interviewer had a custom random shuffler function to shuffle the set. But his shuffler function was not truly random, as he would randomly pick indexes from 0 to the length of the set and swap. This could pick the same indexes twice. It's technically buggy code, but I didn't dare mention something like that in an interview. It goes to show how "strong" the developers working at Tinder are. It also explains the numerous buggy user experiences on the app.)

1. Merge part in merge sort