An API (Application Programming Interface) is used in many different contexts in this industry. To clear this up with our service, read below:
We offer a Common Gateway Interface (CGI). This means your site will need to contain an HTML form or link with cgi parameters appended that passes the correct parameters (and the customer) to our site for checkout. Passing in the Proper Parameters will result in the customer going through the rest of our checkout process (such as entering their credit card information), and after verification, a successful sale.
The following Knowledge Base articles provide more information about the specific parameter sets 2CO uses:
What are the parameters for the Plug n Play cart?
Does your system have it’s own parameters? If so, what are they?
Does your system support Authorize.net parameters? If so, what are they?
What are the New Cart Purchase Parameters? *Required if not using the plug-and-play cart parameter set*