Need a developer to create web-based service

I am seeking a developer to build a website that will provide users with an online business service. I will provide wireframes of the various screens as well as rudimentary descriptions of the back-end logic.

This positing is for the first phase of the project which is to build an alpha version of the website that will proposal the basic functionality of the service. This alpha version will targeted at mobile browsers however the code should be easily extendable for use with tablet and PC browsers in the future.

If all goes well as well as the alpha version is well received there could be substantial follow-on work for the development of the beta version.

The developer will want to be able to handle both the front-end and back-end portions of the website. I'm not a technical person however here's what I think I need-

a) Front-end- web pages must be responsive so that they can be displayed on all popular devices and screen sizes. The pages will not be complex they will consist mostly of text.