I want a site where all engineers across many different levels and areas of expertise can advertise their skills on an easy to use online bulletin board, essentially. So that's why I created InterviewShark. If you'll notice, it's a single page app, with no sign ups. I'm going to add search functionality and ratings in the future, to make it easy to find interviewers. But right now it does what I set out to build -- easy, no nonsense, no signup mock interviews.
I targeted hardware first because that area is very underserved for mock interviews (I used to run this service in the past for https://chipdev.io). But I want to build out the software side. If you're interested in earning a bit of extra cash, feel free to apply to be an interviewer. The onboarding is fast. If you're not a good interviewer then I'll probably have to kick you off, but I doubt that would be a problem for 99% of us.
Also I built out the interview platform myself too, to make this tool exactly how I wanted it: interviewshark.com/sandbox (sandbox version, no collaborative features). It's a pretty simple tool (just websockets for collaborative UI elements + firepad for collaborative editor), but it has all that's needed to do interviews.
Let me know what you think and how I can make this a better tool for the HW and software eng community :)