I’ve reading the API, and it seems that all the calls are made through a client, it is possible for the users to have a API_KEY to access directly the resources? I like a user would like for example to add mnemonics directly in my account (for example add the Cantonese pronunciation). And of course, I wouldn’t like to pay double to maintain a client account.
You can create an API client account without paying, but rather buy using a special coupon code. Have a look at the following page (specifically the signing up section):