This looks like a well thought-out project, but I am unsure how it would realistically fit into an actual project. It claims that "it does not tie you to a web framework", which I guess is technically true... but the amount of setup involved on the server basically makes this thing its own framework (in terms of having to manage it on the back-end). And if you're already using a framework then it most likely includes its own form generation/processing system.

Seems to me that a more practical "framework-agnostic" form library would be one that is completely on the front-end, and assumes a REST-like API exists on the backend that it can communicate with.