First up, initial phone screen with a recruiter. My recruiter was polite, and if you actively engage in conversation this call shouldn't be a problem. I've seen some reviews that say the recruiters were unprofessional - I can't speak to that, mine was good through the process.
Next up, HackerRank. Yes, they use HackerRank. No, these problems aren't always the best way to show your competency. But this is the pattern a lot of companies use these days. I was pleased to see the problem's subject was actually related to Invitae's domain, and not some contrived problem completely unrelated to the business.
No, this problem doesn't spell out word-for-word what it's looking for. Part of this problem is being able to derive the actual requirements based on some instruction. This is similar to how you might do actual work where a product stakeholder is giving requirements - they aren't going to give you the technical details. That's your job. I'd recommend at least getting familiar with HackerRank and how to debug effectively on the platform, that will save you. I was able to complete all test cases, but with only about 1 minute left - although a perfect score isn't needed to continue in the process. Just do the best you can.
The recruiter gave me plenty of time to complete this step, and worked around busy holiday schedules and other work timing obligations.
Next up was a call with a director. They will have seen your HackerRank submission, and might talk briefly about it. Otherwise, this call is more of an initial technical evaluation. This isn't a problem solving call (mine wasn't anyway), but they want to know what you've worked on, what you enjoy, and evaluate how you might fit in their org.
Assuming all goes well, last step is the zoom-based technical & cultural interview. Total time is around 6 hours I think, but they can split it into multiple days if that works better for your schedule (I did this over two days).
My Day 1 was all code. As others mention, they give you a link to a repo 24 hours ahead of the interview. You should really use some time to glance over this, just to get familiar with what's going on. If you haven't looked at the code before the interview, you will 100% get slowed down immediately.
You will be working tickets on a trello board, and you are free to pick whatever you want. Some are frontend focused, some are backend, some are more ops/architectural. During the pair-coding, the key here is to keep talking. Speak out your thought process as you work, and don't be afraid to ask for some guidance if you get stuck. They are there to work with you, but ultimately you need to be supplying the direction.
Next up for me was the cultural interview. Talk, ask questions, be interested and interesting. If you can hold a conversation without making a serious hiccup, you should be fine here.
My final interview was a design/architectural based interview. The format of this was a little difficult, (google slides isn't a great technical interview medium) but my interviewer was very polite and had no problems clarifying or answering any questions I asked. This interview is more system level, and a basic understanding of Relational DBs and cloud architecture will go far here. "How does this button I click here translate to an order submitted way over here?" If you can answer those full-stack types of questions, then this will be pretty straight-forward.
After that, I heard back with an offer in the next 1-2 weeks. Overall, this interview is not easy. But it is fairly thorough and I think they have a fair understanding of your capabilities by the end.