APIs require authentication in the form of a key, which can be created by adding a service in your account. Each key has its own security settings (URL & IP restriction, usage limits),
and as many keys as necessary can be set up with these restrictions. See the Creating API Keys page for more information.
A key must be passed to the API as a parameter in order for the request to authenticate, otherwise an error will be returned.
Each API has specific errors that may be returned, as well as a common set of errors relating to either account or key settings. See the Common errors page
for details.