The SERPs.com API is available to all Enterprise plans and higher. It allows you to access most all data points you see in your SERPs account, including the latest Google and Yahoo rankings for keywords in your account.
There is a good general overview of how to use the API on the SERPs main site.
You'll need to request an API token: request API token.
Once you have a SERPs.com account, and a valid API token, we recommend playing with the API console to familiarize yourself with the API and the resources available to you.