I applied for a Full-Stack (Front-End focused) Software Engineer position after a Twitter recruiter reached out to me. Overall my experience was great. The phone screen included implementing fizz-buzz, string manipulation and a basic tree/graph question. The on-site was short and sweet: only three sessions. The first session was a pairing/realistic challenge to modify a super basic full-stack application, both front-end and back-end. Nothing tricky per se, but you have to be able to debug things a bit as you go and rely on your interviewer(s) for help, just like you would if you were pair programming. The second interview was a system design question where you get to describe how you would implement Twitter (!). The question is obviously very broad and you're dealing with the subject matter experts, so I'd recommend listening carefully to their suggestions and questions and going the way they point you to. Last but not least, I had a resume dig of sorts with the team's manager where we went through my resume and talked about every professional step I've taken, highlights and lowlights, and a fair bit of introspection about strengths and failures! Again, nothing tricky here, just be genuine.