Magento 1.9 send cart info to checkout page using soap api

Question

I'm getting cart info in soap api. Now I want to send this cart info to checkout page using soap api. Like there is app and website of store and I get cart info from app and want to send that cart info to checkout page of website for payment means want to redirect to website checkout page from app. So, I want to know what should be the url of checkout page and what parameters I need to pass in url. Is this possible? Can anyone guide me with this please?