I've spent hours reviewing the API "docs". Ultimately, to repeat the plea I've read over and over again on this board:
I would simply love to see a WORKING example (IN ANY language) of how a website can add an email address to a given Constant Contact mailing list. It would go a long way to see one program that from start to finish authentic with Constant Contact via API V3, adds an email address to a list, drops the authentication token correctly.
Currently, the only complete application code samples we have available are for the V2 API.
V2 Full Code Samples:
The request for V3 application code samples is currently under review. However, we're currently still adding endpoints and capabilities to the V3 API, and do not plan to publish official SDKs or sample apps until that process is complete. Your feedback and experience with this request is essential to improving our product, so thank you for reaching out to us regarding this matter.
In the meantime, here are the example calls that are currently available for V3:
UPDATE: We gave up on the CC API. Looking to other vendors with a more reasonable API.
Anyone unfortunate enough to be stuck in this platform, good luck.
This forum topic:
https://community.constantcontact.com/t5/Getting-Started-with-API-s/V3-Starter-NET-Project/m-p/34029... has some good information on this.
As a summary, currently impossible to do this without a user (you) having a web interaction with CC.
Additionally, in order to have a robust solution running, you are going to have to create some background timers and have them running to update the tokens.
This portion of the API docs give some details about the timer requirements:
(look under the section 'Make access tokens last longer')
One other "gotcha" I ran into before we gave up is the redirect URI my be in your app's details (MyApplications/App details/Redirect URI) and be warned they are case sensitive.