As of February 2020, all new NS1 accounts include an enhanced security feature in which API key secrets are automatically hidden after creation. This helps prevent tokens from being leaked and used for anything other than their intended purposes.
After creating the API key, the user must toggle the show/hide icon and record the key secret before navigating away from the page. NS1 recommends saving the key secret in a secure password manager or key vault.

Admin users for accounts created prior to February 2020 who want to enable this feature on their account can submit a request to the NS1 support team.