I signed up to tier 1 and using the service to verify leads coming from my website to Keap. So far it's working great. Implementation and using the API is straightforward.

I do have one suggestion regarding API Key security:

Right now, the API key is included directly in the URL when making a request. This can be risky because URLs are often logged by browsers, servers, and network tools, making the key visible and potentially exposing it to unauthorized access.

A more secure approach is to send the API key inside the request headers instead. This means instead of putting the key in the URL, it would be placed in the Authorization header of the request. This way, the key remains hidden from logs and referrer headers, reducing the chances of it being leaked.

Otherwise, very happy with the service.