All REST API calls (except the login endpoint) must pass the following header to authenticate the call.
Generated within the Dashboard under Settings > API Key.
Whitelabel account owners will also need to pass an additional header to all calls. Again, this is only required if you signed up for a custom Whitelabel account (where you have your own branded dashboard and domain.)
Your custom Whitelabel ID. If you lost this or did not receive this upon registration, contact us.