Very thorough, challenging, and in-depth technical interview. Be prepared to put a great deal of thought into it.
You'll receive a trial ThousandEyes account in which you'll get to know the platform, how all of the tests work, the results they produce and what they mean. A lengthy take-home assignment is given that will test what you've learned from the platform. There's also a programming exercise that focuses on the ThousandEyes API, and you'll also need to construct a demo that focuses on a technical topic that you're familiar with.
Finally, you'll be expected to present everything via webex or in person. A considerable amount of effort, but it is a great interview process to ensure that they hire the most qualified candidates.