Authentication to the API is performed via HTTP Basic Auth. Provide your API key as the basic auth username value. You do not need to provide a password.
If you need to authenticate via bearer auth (e.g., for a cross-origin request), use
-H "Authorization: Bearer yourapikey" instead of
All API requests must be made over HTTPS. Calls made over plain HTTP will fail. API requests without authentication will also fail.
curl https://api.mergent.co/v2 \ -u yourapikey: # The colon prevents curl from asking for a password.