Looking for SEO Audit API (Free or Cheap)

Looking for a SEO audit API that I can build my own front-end for that generates data similar to http://www.seositecheckup.com
Fairly cheap or Free this is for multiple URL's not a single project more like for a tool to offer to users.

If seeking free help that is one thing but if you want to hire someone, you will need to post in the Hire a Freelancer section, best of luck with your project.