The SoftLayer API bindings load your settings from a number of different locations.
The configuration file is INI-based and requires the softlayer section to be present. The only required fields are username and api_key. You can optionally supply the endpoint_url as well. This file is created automatically by the sl config setup command detailed here: Configuration Setup.
Config Example
[softlayer]
username = username
api_key = oyVmeipYQCNrjVS4rF9bHWV7D75S6pa1fghFl384v7mwRCbHTfuJ8qRORIqoVnha
endpoint_url = https://api.softlayer.com/xmlrpc/v3/
timeout = 40