Jason this looks sweet! I don't ever comment on HN, but I couldn't hold back when I read the post.

I've been writing the same boiler plate code in my API layer as well and have been thinking about something like this for a while. This is the first validation library I've seen that provides the coercion needed when dealing with user generated data. I've seen plenty of libraries that do one or the other, but when you use two libraries you end up duplicating the schema definition or writing custom transformation functions to make the libraries play nicely together.

I haven't play with it yet, but am extremely excited to do so and will post my thoughts soon. Thanks for all the great stuff you and the Prismatic team are putting out; it's greatly appreciated!