Make sure you are not wasting your time, and here is why.
The CTO approached me via a hiring website, and invited me to interview. Then the HR scheduled an initial screening call. She was really nice and excited and informative.
They sent me a screening test and then the CTO invited me to technical interview on-site.
Apparently, he did NOT read my resume, check my linkedin or even check my answer for their challenge. It seemed like he was hiring a DevOps Engineer not a Backend Engineer, because he was really focused about really specific tools that he forgot to ask any backend/engineering related questions.