Unfortunately at this time the ability to activate SimpleShare for automatic posting to your social media is limited to only emails sent from within the Constant Contact user interface. However, it is possible to activate SimpleShare from within your Constant Contact account after an email created through our API has been created and sent. If you are interested in more information about this, you can find it here: https://knowledgebase.constantcontact.com/articles/KnowledgeBase/7518-Create-Posts-Through-Social-Sh...
If you would like, I would be happy to submit a feature request on your half regarding this feature.
Tier 2 Support
Elijah G. API Support Engineer
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