Build a webapplication for Realtime Email Inbox Preview like Litmus

Hello Guys, I want to buildup a web application from where we can check the realtime Email preview for various email agents like gmail,outlook etc similar like Litmus. There is no design i [login to view URL] i need an editor where user will input the email html template with their own code and after submit that will be submitted towards various email agents/client like gmail,outlook etc and after that user can see the preview realtime screenshots of those email agent'[login to view URL] can follow the Litmus website for details idea. Reference website for the idea: [login to view URL] You need to integrate API from them but you can see that their API is not free ,its very much [login to view URL] i need to create the similar tools with free of [login to view URL] let me know your idea asap.i need some idea/progress quickly. You can use any programming language like .net,javascript etc.I only need output.