Gridwise Senior Software Engineer, Backend interview questions

I had an initial screening with a recruiter, and then moved on to the pair programming exercise with 2 of their engineers. I was the first person to take this version of the pair programming exercise (they even called me the guinea pig), and there were some complications (missing libraries in the test environment, so only core Golang), but overall it seemed like a great outcome. I got a follow-up email that they wanted to move forward to the virtual on-site, however I then got a call telling me they wouldn't be moving forward with me after all.