Your API key is found in one of two places, depending on which edition of Campaign Monitor you're using.
You'll know you're using the multi-client edition if the menu option "Clients" is in the navigation:
Multi-client edition API key
You can only access your API key after you have verified your account. This is done by clicking the verification link in the email we sent you after your Campaign Monitor account was created. If you can't find the verification email, please contact support.
To access your API key, click Account Settings in the top navigation bar. If you don't see "Account Settings," you are in a client view and need to click Clients first.
On the next page, below your company name and other details, click Show API Key as pictured here:
Tip: You can authenticate with OAuth instead of an API key.
Client API keys and subscriber list details
For information on developing your own applications to integrate with Campaign Monitor, view our API documentation. It will help you work your way through every stage of the setup process, including instructions for finding things like client ID and list ID information.
Important: Your API key grants access to your account and all of its data, so only use it with trusted third-party websites and applications.