We are planning to start using Constant Contact for mass emailing. Before that i wanted to test the ReST API. Can i create any test account or something which i can use in my test application?
You can use a Trial Constant Contact account to test out both our Constant Contact products and the API. This is a free 60 day trial limited only to 100 active contacts (and other restrictions for our Event Marketing and Survey products, however we do not offer API integration for those products as of now).