No secret key, but you need a secret password? isn't that the same?
The API is accessible without an account! There is no password required to use the api! You only need an account to log in and view the docs.
Probably should make that more obvious... also, why did you reply to my comment twice (once in a completely unrelated post).
The API information is viewable once you create an account so that the API incentivizes signups, which is very common. Once you have the URL you can freely use it without a secret key or without a limit! Every other API like this charges you. API details that are viewable behind a login page is not the same thing as a secret key. A secret key is something you have to input every time you query the API, usually for tracking the number of calls you make and to eventually charge you.