I have been working with ReactJS, Node and Express since 2.5 years ago, these are my main technologies and where I feel more confident working on. Beside that, I have 8 years of web development experience, I worked in all varieties of team sizes. I'm very organized and I like to have a clear estimate of my tasks and how long takes me to finish them.
If I need to choose between Frontend and Backend I pick Frontend because is what I like most, but I feel really comfortable working in both sides.
Since I started in the dev world, I have been working with Agile methodologies mainly with SCRUM.