Don't be so sure about Crunchbase API. It's owned by AOL, which haven't played nicely in the past, too. https://news.ycombinator.com/item?id=6680040
However, at this point crunchbase is pretty open (to the point of giving data dumps) so I'll give them the benefit of doubt for the next 2 years.
Anyway, startups seem to tend towards closing off access to their data as they become the dominant player so it's a question of when not whether.