Is there any way to verify the level of expertise that someone might have, let's say in web development, especially nowadays with this fast-pace evolution of technology that we can't keep up?
What should be considered as the entry basis one should have to get hired?
I've done and helped with a fair amount of hiring for organisations large and small, and some liars are very convincing in email and via agents. Other hirers tell me that their experience is similar.
At some point have the candidates in person in front of you and have them discuss with you something basic but important to make sure that they are not an utter fraud (yes, I've seen it). DO NOT do complicated coding / whiteboard tests which frazzle the wrong people and are somewhat cruel and are unlikely to select the right people. Too many such tests seem to be about the tester's ego, not the testee's value...
It is more to do with the way that a small but significant number of potential hires (and their agents) will fake anything done remotely to get in if your role is good, and you really want to avoid hiring those. And on the other side some smart-arse in-person feel-good test is not the full solution either.
Again, I say this having been on both sides of the hiring process a fair amount.