Are all postdoc jobs advertised? I recently had a postdoc interview (at a research institution) in which I wasn't selected. After receiving the interview outcome, I decided to directly email the panel a few weeks later asking for a feedback. One of the professors replied and invited me for a chat the following week. He said that he has other opportunities that are a good fit for my profile. I know that he's talking about the university where he's working and not the research intuition where I met him (with the panel).
The issue, is that I checked the university's website and I didn't find any job postings. Can a PI hire a postdoctoral researcher without first advertising the job?
Many job postings are written after the candidate that will fill the position has been selected. This makes sense in academia - I usually want to hire people who were trained by people I know. University policies often require that postings are made for all positions though.
It's therefore very common to interview for a position that hasn't formally been posted. Especially if you have fellowship money coming with you.