Get something written down on paper before you do any significant amount of work for them. I went through this and spent several months working full time for a

Get something written down on paper before you do any significant amount of work for them. I went through this and spent several months working full time for a startup only for them to try and screw me over. I had to quit and take the issue to court. The equity share was written down (although not in the form of a contract), but the founder of the startup tried to add on a lot of ridiculous restrictions which would essentially give him the right to strip me of all equity for whatever reason he wanted. If I had had an actual contract he couldn't have done that.