There was an original phone interview to get some basic information about my interests and background.
This quickly moved forward into a technical phone screen, using an online whiteboard (I think coderpad?). The interview was nice: The question was straightforward, building up in complexity as I completed each ask, and the interviewer was very responsive.
Next step was the on-site interview. This started with a quick call with a recruiter to give a general indication of what kinds of questions to expect, and good advice on how I should be able to come up with examples from my work related to all of Twitch's core values, as well as each entry in the responsibilities and requirements for the position. Although they did not ask those questions specifically, the questions they did ask tied in to those concepts, so having thought those out made it simpler to recall the right memory for the questions that they did ask.
The on-site interview was very enjoyable, 1 or 2 people at a time for 45 minute blocks. Each team of people came from a different section, and asked very different questions, from digging into my background in SDET, to a few more short coding problems, to an informal lunch session. The one thing that was very clear the entire time was that everyone seemed like they wanted to be very open and honest about the culture and tasks involved, and were genuinely interested in trying to get a good feel of how I am as a whole as an engineer, instead of just doling out challenges and constantly grilling, looking for flaws and weakness.