In almost all cases a work permit must be tied to a job offer, so it's not possible to apply for a work permit in advance.

You interview, you get the offer, and the lawyers at the company apply for the visa for you.

There are some exception cases where an open-ended visa is possible, but this is uncommon - but if you're famous in the industry you may qualify.

Thank you, Jerry that was very helpful!

I'm a Canadian who recently relocated to SV from London, UK. Before that I was at RIM/BBRY in Waterloo. After receiving my job offer and an invitation letter from the company I flew to the US and, at the border, applied for a "TN Status". Cost me $50 and about an hour and a half. It gives me a 3 year work permit at my employer, which is renewable.

Very fascinating, thanks Kyle!

Particularly for Canadians <-> Americans going across the border int tech, this is made quite easy by the TN "visa" program (it isn't really a visa, but part of the NAFTA agreement).

In other cases, the work status conversation is an important part of hiring and negotiation.

Thanks for this Ska! It's clearer for me now