ExactTarget API

ExactTarget API, http://drupal.org/project/exact_target_api, provides an abstraction of the ExactTarget XML API for use by other modules.

The modules using ExactTarget API are:

• Exact Target Email
• Webform ExactTarget

Configuration

XML API:

• Customers using the S1 instance use this URL to access the ExactTarget XML API:
  https://api.exacttarget.com/integrate.aspx
• Customers using the S4 instance use this URL to access the ExactTarget XML API:
  https://api.s4.exacttarget.com/integrate.aspx
• Customers using the S6 instance use this URL to access the ExactTarget XML API:
  https://api.s6.exacttarget.com/integrate.aspx

Full documentation can be found in README.txt

Why did you choose the XML interface instead of the SOAP interface?

(From http://drupal.org/node/1845168)
At the time the module was originally written, the SOAP layer was poorly documented and required extra privileges to use that interface, whereas the XML API was well-documented and supported on all levels of accounts. The SOAP API may be better documented now than it used to be (it was poorly cross-referenced, had no examples, the DTD's for types were hard to find if even available, and ET support was less than helpful).

The way the API was built, it could be converted to SOAP pretty easily.

See

http://drupal.org/node/1851376