To do well on this interview, all you have to do is watch that video on Frontend Masters. I'm a very experienced developer with 6+ years doing frontend development. I have built, scaled and maintained applications scratch, cleaned up other people's poorly written code. Even though one of my applications is being used by 5M+ users, I did not pass this interview. This approach to qualifying candidates this way is very elitist. Even though the developer I interviewed with had less experience than me when it comes to building a comprehensive and scalable applications, I didn't do well on the phone interview. I feel that most of the JS concepts that was asked is very deep in theory but not something you use in practice. To do well, all you need to do is watch 9hr video from Frontend Masters. If you are a recent college grad and have time to watch that video and read the theory on Javascript, you will do well. This is why they are able to hire mostly college grads. However, even if you watch that video and know the basics on Javascript, it doesn't make you a good front end developer. In their video, they mentioned that there's one concept that 99% of FE developers don't know, which is true. It is also very elitist to say that makes a good FE. Also, it seems that they are consultants to teach companies how to build Javascript applications, but they themselves don't write much code for their clients. They tell their clients how to write code, but they don't do it themselves. They also aren't experts with CSS, HTML5 or most modern libraries, such as AngularJS or React. So you have to decide whether this is the kind of experience you want to acquire over the course of your career. If you work for Bitovi, all you gain is theoretical experience and not practical experience, does it help your career?