The developer team that is developing the official API have closed off the beta. Before, the official API is in a closed beta. The latest update is follows:
I have an update for you all regarding the closed beta we have been running up until now.
Unfortunately, when we opened the beta we made an error in the internal release process, which means we will have to close off the beta for a time. We are currently working on redoing the release process and are trying to have the API’s closed beta out again as soon as possible.
Sorry for the this coming up out of the blue
For now, please use the stable release until the official API is opened up again.
In addition, I will be redoing the donation licensing system for MAL Updater OS X since there have been trouble with license generation. I will be changing it so that online verification will not be required. Existing users who already have a license will be able to get a new license code for free. More details soon.