Hello BrendanS6,
Thank you for reaching out to Constant Contact API Developer Support. My team is here to assist outside software developers with questions about building into Constant Contact's API.
Constant Contact provides developers with free access to our V3 API endpoints for developers building their own application for integration. You can get started using our API by visiting our documentation here:
https://v3.developer.constantcontact.com/api_guide/getting_started.html
Our developer portal uses the same credentials and login session as your Constant Contact account. As a side note though, V3 API keys generated via the Developer Portal are not universal to the account and can only be accessed by the logged in user that created them.
Additionally, you can utilize our API Reference Page to find body schemas & values, as well as test the functionality of our available endpoints to see how they will work once programmed within your application:
https://v3.developer.constantcontact.com/api_reference/index.html
While our expertise is with our API itself as opposed to its implementation within any particular programming language, we are happy to answer any questions pertaining to Constant Contact's API endpoints, functionality, and documentation.
Please have a look and let us know if you have any other questions!
Regards,
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