First: READ ANY NDA THEY SEND YOU COMPLETELY
Short call from Recruiter, Sets up another quick call with someone more technical, then they'll setup an in person interview.
Before the In person interview some major red flags: They ask for 5 professional recommendations and asks that 2 of them be managers/supervisors. They will have a survey that they will email each and every one of them which looks to take at least 10 minutes and may call them. This is unusual and reaching way past normal background checking.
The part that's severely worse than the extreme reference checking is their NDA they send you. They send this NDA before an onsite interview, PRIOR to any offer letter. A section of the NDA I was given had a very overreaching definition of an 'invention' that could be influenced "Directly OR Indirectly" just by your onsite interview.
They specifically ask you to sign that any 'Invention' you develop or in part develop you must notify Bandwidth and help in giving them any 'right, title or interest' you may have in such Inventions to them.