I'm using the SoftLayer REST API, and instead of username and API key, I'd like to authenticate with my IAM token. Is this possible?
This is actually now possible. You can use your IAM api key to authenticate with the Softlayer API now. To do that you can do the following.
curl --location --request GET 'https://api.softlayer.com/rest/v3/SoftLayer_Account?objectMask=networkVlanSpan' \
--header 'Authorization: bearer <your token>'
To get the token run ibmcloud iam oauth-tokens
.