Authenticating your client with the Mad Mimi Email Marketing API is easy. Along with any request, you'll need to pass two parameters. The first is your Username (the email you use to sign in), which identifies the account you're currently using, and the second is a valid API key.
Pass these credentials as a querystring, as shown below:
curl -v -H 'Accept: application/json' -X GET --data "api_key=YOURAPIKEY&username=YOUREMAIL" https://api.madmimi.com/promotions
curl -v -H 'Accept: application/json' "https://api.madmimi.com/promotions?username=YOUREMAIL&api_key=YOURAPIKEY"