The Redirect URI is used in the Oauth 2.0 authentication process. It is the uri that our systems post your an authorization code to, which is then exchanged for an access token which you can use to authenticate subsequent API calls. The redirect URI you include in your API key setup, has to match that which you provide when making your requests during the Oauth 2.0 process. You would need to have a script at this URI that handles the post (or callback) from our systems, calls for the access token, then stores that security for future use on your server for use in your API calls.
You can find a more complete explanation of our implementation of Oauth 2.0 in this article.
I hope this informaiton is helpful. Let me know if you have additional questions.
I read the Redirect URI in API key discussion.
However, it doesn't mean I understand it.
In simple English - do I need this for my BigCommerce e-commerce platform's email marketing integration?
You do need to put in something for the redirect URI in order to generate the API Key, but you can put in a dummy value there if you won't use it. It's my understanding that BigCommerce's integration to us just needs the API Key from you, not a redirect URI, so you can put in a dummy value for the redirect URI (http://yoursite.com for example).
If you use OAuth2, you do need to have a valid redirect URI. This is the URL that the user will be taken to after they grant access to your integration. If you're using basic authentication, you don't need a valid redirect URI.
Support for basic authenticaion will be deprecated in the future. If you need to generate an access token and use a redirect URI (use OAuth2) but aren't sure how, I'd recommend going to this link to generate the items you need to utilize OAuth2.
API Support Specialist