Hello user6030290,
When using the "GET a Collection of Email Campaigns" endpoint, there is not a way to predetermine the amount of pages that will be returned via API. However, to cut down on required calls, you can make sure you are setting the "limit" parameter to the highest available increment of 500. If the "limit" parameter is not specified, the default amount of campaigns returned is only 50.
GET a Collection of Email Campaigns
https://v3.developer.constantcontact.com/api_reference/index.html#!/Email_Campaigns/retrieveEmailCampaignsUsingGET
Please have a look and let us know if you have any other questions!
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