This is a really tough decision and there are lots of things to weigh. 1. The equity sounds all good and well, but you need to know the intentions of the found

This is a really tough decision and there are lots of things to weigh. 1. The equity sounds all good and well, but you need to know the intentions of the founder — would they every consider selling or doing an IPO. If not, your shares will have zero value. 2. What space is the startup in? Do they have a technology where they are both building a moat and growing at a rate where they will be around in 5-10 years? 3. Can you live on 1/3 of what Google is offering you? If you believe your startup is the next Dropbox, Airbnb, Uber, SpaceX or Pinterest I would say join that. The thing about these mega-companies (Google, Apple, Facebook, Microsoft, Amazon) is that they aren't going anywhere and if you made it through the interview already, I'm sure you can do it again. These mega-companies are filled with brilliant people so you will definitely learn a lot about running projects at scale. They are also filled with bureaucracy (unless you're on a skunk works team with no budget) which sucks if you're the type of person that likes to move quickly. In my opinion, a great startup beats any mega-company any day of the week.