REST API security is based on login credentials. No signed documentation is required for access.
Because the SOAP API gives you access to read and send change requests to your database, we require authorized permission.
If you're interested in using the SOAP API, print, complete and fax the Access ACS SOAP API Agreement to 800-227-5990.
Since we're focusing development efforts on Realm, our next generation ministry tool, we're no longer updating Access ACS SOAP APIs.