Column uses basic auth to authenticate the API. You can create sandbox and production keys in the developer dashboard. Live production keys are prefixed with live_ and test sandbox keys are prefixed with test_.

Use your API key as the password, the username should be left blank (notice the colon sign before api-key that has to be included)

$ curl -u :{api-key} https://api.column.com

All requests must be made to https, anything sent to http will fail.