Started uniquely with a POST request containing a payload with my name and email, then spoke with a very friendly HR representative, then had a 1.5 hour technical interview. The technical interview was very relaxed, "open book". Essentially they wanted to see how I operate under a regular work environment. The technical interview was challenging, but I actually enjoyed it.

FlightAware has a transparent interview process. You can read about the whole thing on their engineering blog, and my experience was fairly close to what was described. Before each stage you will receive a full description of what will be covered and what will be expected of you and tips for success. The HR staff is very professional and the processes are well managed. First interview is a straightforward background screening. Second interview is a 90-min tech screen. They state they don't do LC style code-puzzles, but the first 1-2 questions were indeed "do a thing you'll never need to do, without using the standard library" type exercises. After that, the exercises involve some approximation of real data, approaching a similar problem from several angles. Coding is done in an online IDE, and you can use web search and documentation. The interviewers were very friendly and helpful. I bowed out before the third interview, which is a more in-depth system design interview + meet-the-team. Although they don't require a degree to apply for the position, it was clear from the system design interview topics that they expect candidates to have fundamental knowledge gained primarily from CS degree coursework. That's fine, and I appreciated the opportunity to evaluate that fit before making a fool of myself. FlightAware has also recently been acquired, and I sensed some uncertainty (also noted in recent GlassDoor reviews) about the direction the new ownership want to take the company and which products they will prioritize.