API version update

0 Votes

We are getting following email. Check following screenshot :  https://prnt.sc/DY2E6epdkrT1


Now we have the following type of code in our website: https://prnt.sc/yYtVld75ksQp


So we are not sure about how we need to update the authentication process. We have read the documentation, but not getting clear way to do. 

Still we have made the change in code which is following, but it is not working at our end.

Screenshot : https://prnt.sc/f1D93dz0ejz_


Could you please have a look and help us to upgrade


Brand Visionary
0 Votes



Looks like you are using PHP.  The new OAuth2 server requires a more complex handshake than the old one.  It is not a trivial fix.  I would recommend you use my V3 API library, but will require rewriting your code and PHP 8.0.  But the upside is you will be insulated from future changes.  More details here: https://packagist.org/packages/phpfui/constantcontact

0 Votes

Hello JuneL4,


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.


It looks like you received this communication because a V3 API key was previously generated within your account, but based on the code sample that you provided, it looks like you are currently using our legacy V2 API, which will not be affected by the new authorization management service being used for V3.


However, while no date is currently set, there will be a point in the future where our legacy V2 API will begin deprecation, as the deprecation process for our retired V1 API is nearly complete. Due to this, while we will continue to deploy critical bug fixes at this time, we will not be doing any more development for V2 or its endpoints, and strongly recommend upgrading to the V3 API to ensure you're ahead of the curve.


In your second example, it looks like you are using the V3 cross reference endpoints listed within the Data Migration Overview documentation to get a V3 List ID. You can also utilize our API Reference Page to find these values, as well as body schemas, and also test the functionality of our available V3 endpoints to see how they will work once programmed within your application:



As you go through the upgrade process, please feel free to email our team directly/securely at webservices@constantcontact.com with any questions you might have regarding V3’s authentication process, endpoints and functionality.


Courtney E.
Tier II API Support Engineer

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