Activating or starting a campaign will primarily do two things: timestamp the SentAt on the campaign, and set the ExpiresAt to 30 days from now if the ExpiresAt is null or less then 30 days from now.

You do not have to activate a campaign. If you do not Litmus will automatically activate it after it receives 500 opens.

Language
Authentication
Basic
base64
:
Click Try It! to start a request and see the response here!