Build a tool for website, write code and create API

I want to build a tool for my website visitors where they can check their overall website performance by typing their website url. Need someone who can write fresh code or have a customizable copy which can be implemented. But need something good, need some good work. Tool can pull data stats from alexa or through google docs or any other free available data provider. Will be a free tool for public but anyone should be able to embed the tool on their own website with my company credentials. A real user friendly and helpful tool.