how do I delete old api key?
With Constant Contact, an API key is permanent once it is created. However, an API key can be disabled to disallow any form of access to the API while using it. If you would like for use to disable an API key for you, the best way to accomplish that is to send us an email at firstname.lastname@example.org and include the following information:
Your Constant Contact username.
Your exact API key(s) that you want disabled.
If you are able to do that, we can absolutely disable the API key and send you a confirmation.
Tier 2 Support
View API documentation, code samples, get your API key.