An API Key and Secret Key are secret tokens used by Mailjet to authenticate you with our servers. Your Secret Key is displayed only once upon creation, in order to ensure maximum security for your account. Be sure to save the Secret Key in a safe place for future use.
Please note that if you need to reset the Secret Key for any reason, you can do so easily in the app.
The API Key and Secret Key are the values entered into the SMTP parameters when you want to send an email directly from your email client or program.
Also, with API Keys, you are able to create sub-accounts on your Mailjet account. This allows separating your mailings across different API Keys for easier management, account sharing, and reporting.