We now have tenative support for an Open API spec. You can download it from SLDN
Due to the way SLDN is designed, the spec sheet is fairly lengthy and a bit complicated, but perhaps it will be useful.
If you are interested in how the file is generated, check out bin/generateOpenAPI.py
OpenAPI CLI Can be used to generate HTML or whatever else from this document.
$> mkdir generated
$> wget https://sldn.softlayer.com/static/openapi/sl_openapi.json
$> java -jar openapi-generator-cli.jar generate -g html -i sl_openapi.json -o generated/ --skip-operation-example
You will need the --skip-operation-example option otherwise openapi-generator-cli will run out of memory building SLDN objects.