Are you asking for a spin syntax validation service? Something that looks for malformed syntax? I don’t know of one and could use the same.
I have article re-writers that produce rewritten articles in spin syntax and they seem to invariably have errors, particularly with improper use of spaces between spun elements. I wrote some code that looks for those errors and automatically corrects them. I never thought about making it into a service, but if you don’t find anything, let me know and I’ll see what I can do.