Best interview process I've ever had, I felt good from start to finish. The process for me felt like it moved fairly fast, but overall, I guess it was about 4 weeks from start to finish.
I applied online, and heard from a recruiter within 3 business days. We set up a fairly typical screening call for either later that day, or sometime the next day or two. I was told I was moving on that same day, and set up a call with the hiring manager the next day.
I was given a technical challenge, that I turned in within 2-3 business days. It was a fairly practical technical challenge involving answering client questions about the product, SQL searches, and a bit of basic javascript. It was may another 2-3 days before I heard from the recruiter again.
After that, I was moved forward to 4 different interviews: core, technical, customer success, and I don't remember if they called the 4th one something specific but it was with the CS engineering lead. The core interview was compromised of a lot of questions like "tell me about a time when you did something". The CS background was all about customer experience, and of course. the technical interview was... well, technical. Honestly, I spent quite a few hours pouring through the docs and looking over questions in the forums and I was still asked things that sort of stumped me. I just did my best to answer with "well, I'd assume because X, then Y might be true, but I'm not sure."
I heard back from the recruiter within another day or two, and set up a call with the VP of the Customer Success department (and all under that umbrella) for the following week. This interview was a lot of talking about my past experience, but in a way that was super unique and pleasant. For example, I transferred schools, and even though it was like 7 years ago now, I was asked why. I thought it was super pleasant.
I heard back about my offer within 3 days of that. The recruiter was super responsive and I felt like every step of the way Segment wanted me to join their team as much as I wanted to join their team. :)