From my perspective that amounts to an enormous cut. I understand that you guys are attempting to mitigate the not-getting-paid risk, but I've been able to do that on my own by choosing good clients. My feedback would be:

1) find a way to disclose the details of how this works for developers on the landing page or on a linked FAQ. I'm simply not going to "Get Started" if I think crucial details are being withheld from me. The pitch put me on the defensive from step 1 which is not a good place to start.

2) Think about adding tiering to your pricing. 10% could make sense for freelances who are just getting started and need to establish themselves with some initial portfolio work but I don't think it makes sense for higher paid freelancers who would otherwise still consider using your platform to find new and interesting projects.

On a positive: the layout and design of this landing page are very well done. The page is very easy to scan and the draw to the call to action button is palpable without feeling salesy or un-balanced.