The API key can't be retrieved from the Netcore email API panel, as this will be hidden after creation.
You can create a new API key in case you have lost the existing API key.
You can follow below-given steps in order to Create a new API key for your Netcore account,
1. Login to your Netcore account, URL: https://email.netcorecloud.com/
2. Go to Settings -> Integrations - > API> Click on Generate API key.
Please Note : You should always copy and save the API keys at your end for future reference as the same will be hidden on the panel once generated. It can take 20 mins for the API key to sync across all our servers post which you can start using the API key to send emails.